Head and neck imaging 9781604061932, 1604061936

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RadCases

RadCases Head and Neck Imaging Edited by

Series Editors

Gaurang Shah, MD

Jonathan Lorenz, MD

Jeffrey Wesolowski, MD

Hector Ferral, MD

Associate Professor Department of Radiology University of Michigan Ann Arbor, Michigan

Assistant Professor and Associate Neuroradiology Division Director Department of Radiology University of Michigan Ann Arbor, Michigan

Associate Professor of Radiology Department of Radiology The University of Chicago Chicago, Illinois

Senior Clinical Educator NorthShore University HealthSystem Evanston, Illinois

Jeanie Choi, MD

Assistant Professor Department of Diagnostic and Interventional Imaging McGovern Medical School The University of Texas Health Science Center Houston, Texas

Elliott R. Friedman, MD

Assistant Professor Department of Diagnostic and Interventional Imaging McGovern Medical School The University of Texas Health Science Center Houston, Texas

Thieme New York • Stuttgart •Delhi •Rio de Janeiro

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Executive Editor: William Lamsback Managing Editor: J. Owen Zurhellen IV Associate Managing Editor: Kenneth Schubach Editorial Assistant: Naamah Schwartz Director, Editorial Services: Mary Jo Casey Production Editor: Teresa Exley, Maryland Composition International Production Director: Andreas Schabert Vice President, Editorial and Electronic Product Development: Vera Spillner International Marketing Director: Fiona Henderson Director of Sales, North America: Mike Roseman International Sales Director: Louisa Turrell Senior Vice President and Chief Operating Officer: Sarah Vanderbilt President: Brian D. Scanlan Compositor: MPS Limited Library of Congress Cataloging-in-Publication Data Names: Shah, Gaurang, author. | Wesolowski, Jeffrey (Jeffrey Robert), author. | Choi, Jeanie (Jeanie M.), 1973- author. | Friedman, Elliot R., author. Title: RadCases head and neck imaging / Gaurang Shah, Jeffrey Wesolowski, Jeanie Choi, Elliot R. Friedman. Other titles: Head and neck imaging | RadCases. Description: First edition. | New York : Thieme, [2016] | Series: RadCases | Includes bibliographical references and index. Identifiers: LCCN 2016022119 (print) | LCCN 2016022904 (ebook) | ISBN 9781604061932 (paperback) | ISBN 9781604061949 (eBook) | ISBN 9781604061949 Subjects: | MESH: Head—radiography | Neck—radiography | Diagnostic Imaging—methods | Diagnosis, Differential | Case Reports Classification: LCC RC936 (print) | LCC RC936 (ebook) | NLM WE 700 | DDC 617.5/107572—dc23 LC record available at https://lccn.loc.gov/2016022119

Important note: Medicine is an ever-changing science undergoing continual development. Research and clinical experience are continually expanding our knowledge, in particular our knowledge of proper treatment and drug therapy. Insofar as this book mentions any dosage or application, readers may rest assured that the authors, editors, and publishers have made every effort to ensure that such references are in accordance with the state of knowledge at the time of production of the book. Nevertheless, this does not involve, imply, or express any guarantee or responsibility on the part of the publishers in respect to any dosage instructions and forms of applications stated in the book. Every user is requested to examine carefully the manufacturers’ leaflets accompanying each drug and to check, if necessary in consultation with a physician or specialist, whether the dosage schedules mentioned therein or the contraindications stated by the manufacturers differ from the statements made in the present book. Such examination is particularly important with drugs that are either rarely used or have been newly released on the market. Every dosage schedule or every form of application used is entirely at the user’s own risk and responsibility. The authors and publishers request every user to report to the publishers any discrepancies or inaccuracies noticed. If errors in this work are found after publication, errata will be posted at www.thieme.com on the product description page. Some of the product names, patents, and registered designs referred to in this book are in fact registered trademarks or proprietary names even though specific reference to this fact is not always made in the text. Therefore, the appearance of a name without designation as proprietary is not to be construed as a representation by the publisher that it is in the public domain.

Copyright © 2016 by Thieme Medical Publishers, Inc. Thieme Publishers New York 333 Seventh Avenue New York, NY 10001 USA 1-800-782-3488, [email protected] www.thieme.com Thieme Publishers Stuttgart Rüdigerstrasse 14 70469 Stuttgart, Germany +49 [0]711 8931 421, [email protected] Thieme Publishers Delhi A-12, Second Floor Sector-2, Noida-201301 Uttar Pradesh, India +91 120 45 566 00, [email protected] Thieme Publishers Rio de Janeiro, Thieme Publicações Ltda. Edifício Rodolpho de Paoli, 25º andar Av. Nilo Peçanha, 50 – Sala 2508 Rio de Janeiro 20020-906, Brasil +55 21 3172 2297 Printed in the United States by Sheridan Press ISBN 978-1-60406-193-2 Also available as an e-book: eISBN 978-1-60406-194-9

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This book, including all parts thereof, is legally protected by copyright. Any use, exploitation, or commercialization outside the narrow limits set by copyright legislation, without the publisher’s consent, is illegal and liable to prosecution. This applies in particular to photostat reproduction, copying, mimeographing or duplication of any kind, translating, preparation of microfilms, and electronic data processing and storage.

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RadCases Series Preface The ability to assimilate detailed information across the entire spectrum of radiology is the Holy Grail sought by those preparing for the American Board of Radiology examination.  As enthusiastic partners in the Thieme RadCases Series who formerly took the examination, we understand the exhaustion and frustration shared by residents and the families of residents engaged in this quest. It has been our observation that despite ongoing efforts to improve Webbased interactive databases, residents still find themselves searching for material they can review while preparing for the radiology board examinations and remain frustrated by the fact that only a few printed guidebooks are available, which are limited in both format and image quality.  Perhaps their greatest source of frustration is the inability to easily locate groups of cases across all subspecialties of radiology that are organized and tailored for their immediate study needs. Imagine being able to immediately access groups of high-quality cases to arrange study sessions, quickly extract and master information, and prepare for theme-based radiology conferences. Our goal in creating the RadCases Series was to combine the popularity and portability of printed books with the adaptability, exceptional quality, and interactive features of an electronic case-based format. The intent of the printed book is to encourage repeated priming in the use of critical information by providing a portable group of exceptional core cases that the resident can master.  The best way to determine the format for these cases was to ask residents from around the country to weigh in. Overwhelmingly, the residents said that they would prefer a concise, point-by-point presentation of the Essential Facts of each case in an easy-to-read, bulleted format.  This approach is easy on exhausted eyes and provides a quick review of Pearls and Pitfalls as information is absorbed during repeated study sessions. We worked hard to choose cases that could be presented well in this format, recognizing the limitations inherent in reproducing high-quality images in print. Unlike the authors of other case-based radiology

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review books, we removed the guesswork by providing clear annotations and descriptions for all images.  In our opinion, there is nothing worse than being unable to locate a subtle finding on a poorly reproduced image even after one knows the final diagnosis. The electronic cases expand on the printed book and provide a comprehensive review of the entire subspecialty. Thousands of cases are strategically designed to increase the resident’s knowledge by providing exposure to additional case examples—from basic to advanced—and by exploring “Aunt Minnie’s,” unusual diagnoses, and variability within a single diagnosis. The search engine gives the resident a fighting chance to find the Holy Grail by creating individualized, daily study lists that are not limited by factors such as radiology subsection.  For example, tailor today’s study list to cases involving tuberculosis and include cases in every subspecialty and every system of the body. Or study only thoracic cases, including those with links to cardiology, nuclear medicine, and pediatrics. Or study only musculoskeletal cases. The choice is yours. As enthusiastic partners in this project, we started small and, with the encouragement, talent, and guidance of Tim Hiscock at Thieme, we have continued to raise the bar in our effort to assist residents in tackling the daunting task of assimilating massive amounts of information. We are passionate about continuing this journey, hoping to expand the cases in our electronic series, adapt cases based on direct feedback from residents, and increase the features intended for board review and self-assessment. As the American Board of Radiology converts its certifying examinations to an electronic format, our series will be the one best suited to meet the needs of the next generation of overworked and exhausted residents in radiology. Jonathan Lorenz, MD Hector Ferral, MD Chicago, IL

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Preface This Head and Neck Imaging contribution to the RadCases series is a highly useful asset to the radiologist, otolaryngologist, and head and neck surgeon. The practitioners in this field are some of the finest diagnosticians in medicine. They have to be. And the best way to prepare for a career as a head and neck specialist is to study all aspects associated with the field so that you can develop your skills during training and on the job. Certainly, the use of radiology stands at the forefront of medical analysis in most medical fields and at the very top of the list for the head and neck practitioner. Using the best tools—such as this book and its associated online cases—will assist you as you strive for perfection. In this volume, the many cases cover a wide selection of patient presentations. As is typical with the RadCases

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series format and the cases covered, this book is written for the radiology trainee and resident to help prepare for the American Board of Radiology examination. This volume is a useful tool that readers can go back to again and again, and its breadth, in addition to the supplemental cases available online, will assist in gaining board certification. Radiology residents will be encouraged by the scope of the covered specialties and subspecialties. The volume builds one’s confidence, not only to correctly answer questions on the board exam, but—and more importantly—as a real-life radiologist dealing with the most important people in a doctor’s life: the patients.

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1

Case 1

A

B

C

■■ Clinical Presentation A 7-year-old girl presents with painful right orbital proptosis.

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■■ Imaging Findings

A

B

C

(A–C) Axial postcontrast CT images of bone (A) and soft tissue (B); algorithms were obtained along with a coronal soft tissue reformat (C). There is extensive right periorbital and intraorbital soft tissue swelling. A rim-enhancing fluid collection is present along the right lamina papyracea (arrow). The adjacent right ethmoid sinuses are extensively opacified (arrowheads).

■■ Differential Diagnosis •• Subperiosteal abscess: By far, the most likely diagnosis given the ethmoid sinus disease, fluid collection, and adjacent inflammatory changes. •• Orbital pseudotumor: Can present with painful proptosis and postseptal inflammatory changes; however, fluid collection is not a feature of this disease process and there is no association with paranasal sinus disease. •• Orbital rhabdomyosarcoma: Presents as a retro-orbital lesion; however, usually is a painless process without associated preseptal soft tissue and sinus infiltration.

frontal) disease. Bony destruction, however, does not always occur, as bacteria can travel via venules between the sinuses and the orbit. Intravenous antibiotics must be administered. •• Subperiosteal abscess is the extreme end of the spectrum of orbital cellulitis, usually presenting as fluid collection between the lateral rectus and the lamina papyracea. Surgical treatment is often required to prevent further complications, such as optic nerve compression.

� Pearls & � Pitfalls ÛÛ Orbital postseptal cellulitis is almost always seen

■■ Essential Facts •• Orbital infectious processes are generally divided into preseptal and postseptal. •• Preseptal “periorbital” cellulitis can be due to several causes including trauma, dental disease, and adjacent soft tissue inflammatory disease. •• Postseptal “orbital” cellulitis is almost always seen in the associated setting of paranasal sinus (ethmoid or

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secondary to adjacent paranasal sinus disease.

ÚÚ Orbital cellulitis requires IV antibiotics to avoid

complications such as cavernous sinus thrombosis and intracranial extension of infection. ÚÚ Subperiosteal abscesses often require drainage to avoid further complication of visual loss due to elevated intraorbital pressure.

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Case 2

A

B

■■ Clinical Presentation A 59-year-old man presents with diminished sense of taste and smell and nasal congestion. An expansile, lobulated, mildly hyperattenuating soft tissue mass is seen at left nasal cavity, extending intracranially into the floor of anterior cranial fossa. MRI of sinonasal region was performed.

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■■ Imaging Findings

A

C

B

(A–C) MRI of maxillofacial region shows a large, expansile, lobulated sinonasal mass with intermediate high T1 signal, heterogeneous but predominantly intermediate to high T2 signal, and patchy postcontrast enhancement extends into the region of olfactory groove.

■■ Differential Diagnosis •• Esthesioneuroblastoma: A dumbbell-shaped mass with a waist at cribriform plate, inferior extension at upper nasal cavity, and superior intracranial extension with peripheral tumor cyst at tumor–brain margin most likely represents an esthesioneuroblastoma. •• Sinonasal squamous cell carcinoma: It is more common in maxillary antrum than the nasal cavity. Also, on postcontrast studies, the intensity of enhancement is less avid. •• Olfactory meningioma: Predominantly intracranial; exhibits dural tail and rarely invades the nasal cavity. •• Sinonasal undifferentiated carcinoma: Usually seen in older population; very aggressive mass is seen, not confined to cribriform plate. •• Sinonasal lymphoma: It is mainly confined to sinonasal region and does not enhance as avidly.

■■ Essential Facts •• Bimodal peak in second and sixth decades. It is usually seen in adolescent or middle-aged patient presenting with unilateral nasal obstruction and mild epistaxis. •• It could be polypoid when small and dumbbell-shaped when large.

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•• Vascular neoplasm of olfactory groove with epicenter below the floor of anterior cranial fossa. Erosive skull base changes and intracranial extension are very common.

■■ Other Imaging Findings •• On CT, a homogenously enhancing mass causing enlargement of nasal cavity with simultaneous bone destruction of cribriform plate area is common. •• On MRI, low to intermediate T1 signal mass, which exhibits intermediate to high T2 signal and elevated homogenous tumor enhancement. There may be a cyst at the tumor–brain interface that displays high T2 signal.

� Pearls & � Pitfalls ÛÛ A dumbbell-shaped mass with a waist at cribriform

plate, inferior extension at upper nasal cavity, and superior intracranial extension with peripheral tumor cyst at tumor–brain margin most likely represents an esthesioneuroblastoma. ÚÚ Areas of hemorrhage within tumor can result in heterogeneous tumor matrix.

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Case 3

A

B

C

■■ Clinical Presentation A 40-year-old man presents with facial swelling.

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■■ Imaging Findings

A

B

C

(A–C) Axial and coronal contrast-enhanced CT images of the orbits. There is diffuse enlargement of the right lacrimal gland (arrow) without adjacent stranding. The remainder of the orbit has a normal appearance.

■■ Differential Diagnosis •• Lacrimal gland lymphoma: In a patient with diffuse asymmetrical enlargement of the gland, this ranks highly on the list of differential diagnoses. •• Sjögren or other lymphoid lesions: This would be a good second choice from the list, as it also can present with diffuse enlargement. •• Salivary gland tumor: Less likely, as such cases tend to present with a focal mass within the affected gland.

■■ Essential Facts •• Lacrimal gland lesions are typically divided into inflammatory (sarcoid, infection, etc.) and neoplastic processes (lymphoid tumors and salivary gland lesions), as these are the tissues that make up the gland. •• Inflammatory and lymphoid lesions tend to affect the gland diffusely, whereas salivary gland tumors tend to be more focal. •• Patients with lacrimal gland lymphoma may be asymptomatic or complain of visual change or cosmetic alterations. •• Lacrimal gland lymphomas constitute ~50% of lacrimal gland tumors and, as noted previously, typically present

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with diffuse glandular enlargement on cross-sectional imaging. •• Diagnosis is confirmed on biopsy. Full body workup must be performed in such patients to assess for distant disease which will alter therapy.

■■ Other Imaging Findings •• MRI can be helpful in suggesting a lymphoid lesion. •• Relative T2 shortening and restricted diffusion can be seen in such cases, likely due to increased cellularity of the lesions.

� Pearls & � Pitfalls ÛÛ Inflammatory processes, lymphoid and salivary gland

tumors make up the majority of lacrimal gland lesions.

ÛÛ Of tumors, 50% tend to be lymphoid in origin, whereas the remainder are usually salivary gland neoplasms.

ÚÚ Full body staging must be performed in patients with lacrimal gland lymphoma to assess the full extent of disease.

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Case 4

A

B

■■ Clinical Presentation A 20-year-old presents with progressive bilateral sensorineural hearing loss, pulsatile tinnitus, and right facial nerve palsy.

■■ Further Work-up CT scan of temporal bones shows irregular, destructive processes at bilateral temporal bones. MRI of posterior fossa is performed.

C

E

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D

F

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■■ Imaging Findings

A

D

B

E

■■ Differential Diagnosis •• Endolymphatic sac tumor (ELST): Destructive soft tissue lesion originating in the retrolabyrinthine posterior surface of petrous temporal bone, involving semicircular canals and vestibule and spreading to middle ear cavity. •• Schwannoma of jugular foramen: The lesion is centered in jugular foramen and does not involve the retrolabyrinthine temporal bone. •• Cholesterol granuloma petrous apex: The lesion is centered in petrous apex and the whole lesion exhibits high T1 signal on MRI. •• Metastatic deposits from renal cell carcinoma or papillary thyroid carcinoma: These lesions are very destructive and do not exhibit any calcification of the posterior limb. It also lacks the high T1 signal foci on MRI. •• Jugulotympanicum and glomus jugulare paraganglioma: The lesion is centered in the jugular foramen and then involves the middle ear and does not involve the retrolabyrinthine temporal bone.

C

F

(A) An irregular destructive infiltrating right temporal bone mass (white arrow) arising posterior to the cochlea in the retrolabyrinthine area. (B) An irregular destructive infiltrating left temporal bone mass arising from the retrolabyrinthine area (white arrow) extending into the petrous apex (white arrowhead) and into the middle ear cavity (black arrow). (C) T1-weighted image exhibits large, irregular, lobulated, bilateral temporal bone masses. The smaller rightsided mass exhibits low T1 signal (white arrow), whereas the larger left-sided mass has lobulations with high T1 signal (black arrow) as well as low T1 signal. (D) T2-weighted image shows bilateral heterogeneous masses with high T2-signal areas suggestive of vascular masses (white arrows). Some of the high T1 signal lobulations exhibit low T2 signal, suggestive of hemorrhagic products (black arrow). (E) Postcontrast images exhibit intense enhancement of low T1 and high T2 signal areas (white arrows). Very little enhancement is seen at hemorrhagic lobulations. (F) Endovascular angiography of right external carotid artery (ECA) shows tumor blush supplied by ascending pharyngeal artery (black arrow).

contain perioperative bleeding. Radiation therapy is for unresectable lesions or nonsurgical candidates.

■■ Other Imaging Findings •• On CT, a thin rim of calcification is seen along the posterior margin of tumor with presence of spiculated calcifications within the mass. •• On MRI, a majority exhibit foci of high T1 signal along the margin or within the mass, presence of flow voids, and heterogeneous contrast enhancement. •• On angiography, a hypervascular tumor blush is seen. •• Vascular supply is seen from ECA and, when more than 3 cm in size, also from internal carotid artery and posterior circulation. •• MRA and MRV are needed to evaluate vascular relationships.

� Pearls & � Pitfalls ■■ Essential Facts •• Slow-growing but aggressive adenomatous or cystadenomatous tumor arising from low columnar or cuboidal cellular lining of the endolymphatic sac. •• Most lesions are spermatic, but 15% of patients with von Hippel-Lindau (VHL) disease develop ELST. •• Sensorineural hearing loss is present in all the patients. Other symptoms include facial nerve palsy, pulsatile tinnitus, and vertigo. •• Treatment includes complete surgical dissection with white margins. Presurgical embolization is performed to

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ÛÛ Destructive lesion centered at the retrolabyrinthine

portion of the posterior surface of the petrous temporal bone with presence of bony spicules on CT and high T1 signal foci and flow voids on MRI in a patient with sensorineural hearing loss. ÚÚ On detection of ELST, check patient and family history for VHL. In that case, screening of the patient for cerebellar and spinal cord hemangioblastoma, pheochromocytoma, renal cell carcinoma, and renal and pancreatic cysts should be performed.

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Case 5

A

B

■■ Clinical Presentation A 28-year-old woman presents with decreased left eye vision over 1 week with accompanying left eye pain.

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■■ Imaging Findings

A

B

Coronal T2 (A) and T1 postcontrast images with fat saturation (B) were obtained and demonstrate a slightly enlarged left optic nerve with mild T2 prolongation and contrast enhancement (arrowheads).

■■ Differential Diagnosis •• Demyelinating optic neuritis: In a young woman with this clinical presentation, enhancement and T2 prolongation of the affected nerve would strongly suggest this diagnosis. •• Optic nerve glioma: Less likely diagnosis, given the age of the patient and the onset and type of clinical findings. However, a small/early tumor could have a similar appearance. •• Lyme disease: Radiographically can appear identical to optic neuritis. Therefore, one must correlate with clinical setting, particularly with regard to rashes, arthralgias, and other CNS findings.

■■ Essential Facts •• Optic neuritis is an idiopathic inflammatory demyelinating disorder of the optic nerves. Can involve any segment of the nerve including the chiasm.

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•• Can be an isolated episode. However, 30 to 40% of such patients will go on to have multiple sclerosis. •• Clinically, affected patients will present with vision loss (often involving loss of color vision) and eye pain. •• Most patients will recover spontaneously. Corticosteroids may be of benefit to hasten improvement. •• Disease involvement with concomitant spine involvement (and lack of brain imaging findings) is known as Devic disease or neuromyelitis optica.

� Pearls & � Pitfalls ÛÛ Optic neuritis can be bilateral in ∼25 to 30% of cases. ÚÚ Multiple sclerosis can be seen in such patients, as noted above, and thus evaluation of brain parenchyma on available imaging sequences is advised. ÚÚ Other disease processes can involve the optic nerve (such as Lyme disease, HIV, and TB) and produce a similar radiographic appearance.

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Case 6

A

B

■■ Clinical Presentation A 40-year-old woman presents with pulsatile tinnitus, hearing loss, and progressively worsening headaches with new symptoms of nausea, vomiting, unsteady gait, and dysphagia.

■■ Further Work-up MRI of posterior fossa is performed.

C

E

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D

F

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■■ Imaging Findings

A

D

B

C

E

F

(A) Postcontrast CT shows a densely enhancing, large, lobulated posterior fossa mass (arrow) extending into an enlarged left jugular foramen. Enhancing serpentine blood vessels are visualized within and around the mass. (B) Bone window exhibits permeative erosive margins of enlarged jugular foramen with erosion of jugular spine (arrow). (C, D) Large lobulated, dumbbellshaped intermediate T1 signal and high T2 signal extra-axial posterior fossa mass with a large number of high velocity flow voids (arrow) extending into the jugular fossa. (E, F) An intensely enhancing jugular fossa mass (arrow) with large flow voids is in close proximity to the left sigmoid sinus.

■■ Differential Diagnosis

■■ Other Imaging Findings

•• Glomus jugulare paraganglioma: Jugular fossa mass without extension into middle ear cavity with permeative bone changes along the margins of jugular fossa on CT, erosion of jugular spine, and presence of flow voids on MRI. •• Jugular foramen meningioma: Permeative/hyperostotic bony changes are seen on CT and dural tail on MRI. •• Jugular foramen schwannoma: Smooth enlargement of jugular foramen is seen on CT with dumbbell-shaped spread along the course of cranial nerves IX to XI. •• High riding or dehiscent jugular bulb: Smooth enlargement of jugular foramen with intact bony margins on CT without evidence for a soft tissue mass.

•• On CT, erosion of jugular spine with permeative, erosive margins of jugular fossa. •• On MR, intermediate T1 signal. In case of subacute hemorrhage within the tumor, salt-and-pepper appearance may be seen with high-signal “salt” areas due to subacute hemorrhage. High velocity low T1 signal flow voids represent pepper. On T2-weighted images, the mass appears hyperintense. •• On angiography, a hypervascular mass is seen with enlarged arteries supplying the mass with intense tumor blush and early venous drainage. Most common arterial supply is from ascending pharyngeal branch of external carotid artery. 18 •• On CT-PET, intense F -FDG uptake is seen. This is useful to monitor response to therapy and detection of metastasis.

■■ Essential Facts •• Arises from glomus bodies which are composed of chemoreceptor cells, derived from primitive neural crests. •• There is a 4:1 female-to-male predominance; common age group is 40 to 60. •• Most common clinical presentation is objective feeling of pulsatile tinnitus. •• Sporadic disease is multicentric ~5% of the time. However, when familial, the incidence of multicentricity can reach from 25 to 50%. •• Treatment: surgery only for smaller masses, radiation only for older population, both surgery and radiation for larger lesions. Presurgical embolization is increasingly used.

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� Pearls & � Pitfalls ÛÛ A permeative destructive jugular fossa mass on CT with salt-and-pepper appearance on MRI and multiple high velocity flow voids in a middle-aged woman with pulsatile tinnitus is the most common presentation. ÚÚ Metastatic lesions to jugular fossa and highly vascular jugular fossa schwannoma can have a similar imaging appearance.

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Case 7

A

B

C

D

■■ Clinical Presentation A 16-year-old boy presents with facial asymmetry.

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■■ Imaging Findings (A–D) There is expansion of multiple bones with an internal matrix that has a “ground glass” appearance (arrows). Note the preserved, but slightly narrowed, foramen rotundum (arrowhead) and vidian canal (curved arrow).

A

B

D

C

■■ Differential Diagnosis •• Fibrous dysplasia: In a young patient, this is the most likely diagnosis given the osseous expansion and typical “ground glass” internal matrix, as noted. •• Paget disease: Can have a similar appearance. However, the cortex of affected bones is generally expanded as well. This is, moreover, a disease process of later adulthood. •• Metastatic disease: Neuroblastoma and osteosarcoma are two primary neoplasms known to have blastic metastases. But these are much less common and typically have a much more aggressive and heterogeneous appearance.

■■ Essential Facts •• Osseous process where normal medullary bone is replaced by fibro-osseous tissue. This leads to bony expansion, with loss of the normal internal architecture. The resultant bone can have a variety of appearances internally due to the varying amount of ossified matrix. •• Usually a monostotic process (70–80%) and can affect any bone. •• Polyostotic disease is typically unilateral in presentation but can be bilateral and symmetric.

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•• Involvement of the craniofacial bones can lead to cranial nerve dysfunction secondary to skull base neural foraminal narrowing. •• Fibrous dysplasia associated with precocious puberty and café au lait spots is referred to as McCune-Albright syndrome.

■■ Other Imaging Findings •• MRI may demonstrate an aggressive enhancing lesion with enhancement. Remember, such findings should always be correlated with radiographs or CT to avoid misdiagnosis. •• Technetium-99m bone scans typically are nonspecific for diagnostic purposes.

�Pearls & � Pitfalls ÛÛ Common condition that should not be misdiagnosed as something more malignant.

ÚÚ However, pain with findings of fibrous dysplasia can

herald malignant transformation to a sarcoma (rare).

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Case 8

A

B

C

■■ Clinical Presentation A 48-year-old woman presents with hearing loss, voice changing over 2 years, and difficulty with chewing and swallowing.

■■ Further Work-up MRI of posterior fossa is performed.

D

F

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E

G

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■■ Imaging Findings

A

B

F

C

G

D

(A) On noncontrast CT, an isodense extra-axial mass is barely discerned (white arrow). (B) Postcontrast CT shows a densely enhancing broad dural-based mass (white arrow) with a dural tail extending in left jugular foramen. (C) Bone window exhibits hyperostotic permeative margins (white arrow) of narrowed jugular foramen. (D, E) Broad dural-based extra-axial mass extending into the jugular foramen (white arrow) appears isointense to brain parenchyma on T1- and T2-weighted images. There is an enlarged extra-axial space surrounding the mass (white arrow) with high T2 signal fluid collection in left mastoid space (black arrow) likely due to obstruction of eustachian tube. (F, G) Intensely enhancing jugular fossa mass (short arrow) without flow voids invades left sigmoid sinus (long arrow).

■■ Differential Diagnosis •• Jugular foramen meningioma: An isodense, strongly enhancing posterior skull mass extending into the jugular fossa is seen with permeative/hyperostotic bony changes along the margins on CT. A broad dural-based intensely enhancing iso T1 and T2 signal mass with dural tail extending into the jugular fossa without high velocity flow voids is seen on MRI. Prolonged tumor blush extending well into late venous phase on angiography. •• Glomus jugulare paraganglioma: Jugular fossa mass without extension into the middle ear cavity with permeative bone changes along the margins of the jugular fossa on CT, erosion of jugular spine, and presence of flow voids on MRI. Short but intense tumor blush is seen on angiography. •• Jugular foramen schwannoma: Well-circumscribed mass with smooth enlargement of the jugular foramen without hyperostotic/permeative bony margins can be seen on CT with tubular spread along the course of cranial nerves IX to XI. •• High riding or dehiscent jugular bulb: Smooth enlargement of jugular foramen (dehiscent) with intact bony margins on CT without evidence for a soft tissue mass. Increased signal is not seen on all MR sequences.

■■ Essential Facts •• Arises from arachnoidal cells of the meninges that can follow cranial nerves IX to XI into the jugular fossa and into the nasopharyngeal carotid space. •• There is 2:1 female-to-male predominance; common age group is 40 to 60 years old. •• Third most common soft tissue mass of the jugular fossa after paraganglioma and schwannoma. Most common clinical presentation is cranial nerve IX to XI neuropathy. Tinnitus and additional cranial neuropathy from cranial nerves VII to XII may also be encountered. •• Morphologically, it can be lobulated or en plaque (like this one). The en plaque variety is more likely to involve underlying dura and infiltrate adjacent bone.

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E

•• Treatment is surgical removal with preoperative hemostasis. Radiation is utilized only for older population with contraindication for surgery.

■■ Other Imaging Findings •• On CT, a dural-based iso- to hyperdense mass that may show areas of calcification with strong homogeneous postcontrast enhancement. On bone windows, there are permeative/hyperostotic bony changes at the margins of the tumor and around the jugular fossa. •• On MR, a broad dural-based mass that is isointense to parenchymal cortex on T1- and T2-weighted images is seen as expected in a meningioma with intense postcontrast enhancement. There is lack of high velocity serpentine low T1 and T2 signal flow voids. •• On angiography, there is a prolonged tumor blush that extends well into the late venous phase. The tumor center is supplied by dural branches of the external carotid artery. The periphery of meningioma in the jugular fossa is supplied by pial branches of the internal carotid artery. Presurgical angiography is essential to evaluate the collateral arterial and venous circulation. Presurgical embolization helps control perioperative bleeding.

�Pearls & � Pitfalls ÛÛ On CT, iso- to hyperdense dural-based mass which

may show calcification with permeative and hyperostotic bony margins of the jugular fossa. On MRI, a dural-based intensely enhancing mass with dural tails extending into the jugular fossa with isointense T1 and T2 signal. There is lack of high velocity flow voids. ÚÚ Meningioma of jugular fossa may mimic glomus jugulare paraganglioma clinically and sometimes on imaging. It is the most important differential diagnosis to rule out.

20/05/16 11:12 AM

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Case 9

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■■ Clinical Presentation A 17-year-old boy presents with epistaxis.

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20/05/16 11:10 AM

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■■ Imaging Findings

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(A, B) Contrast-enhanced axial CT images demonstrate an intensely enhancing mass lesion within the left nasal cavity (arrow), extending through the sphenopalatine foramen into the adjacent pterygopalatine fossa (asterisk). Enhancement pattern is vascular, and there is widening of the sphenopalatine foramen rather than frank bony destruction.

■■ Differential Diagnosis •• Juvenile nasopharyngeal angiofibroma (JNA): Must be excluded in an adolescent male who presents with unilateral nasal blockage and/or epistaxis. This is the number one differential. •• Inverted papilloma: Can have a similar appearance radiographically but is not typically found in this location (usually more anterior within the nasal cavity) or in this age range (usually older men). •• Squamous cell carcinoma: Can present clinically in a similar fashion but again tends to occur in an older population. Lesions tend to have more aggressive features and are not as vascular.

■■ Essential Facts •• JNAs are benign tumors found almost exclusively in young men, in the adolescent age range. Malignant transformation of such lesions is rare. •• JNAs usually present with nasal obstruction, epistaxis, and/or headache. •• These are primarily vascular lesions radiographically and typically enhance strongly on contrast-enhanced CT. Variable amounts of adjacent stromal tissue may be present.

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•• JNAs are typically found centered within the posterior nasal cavity, near the sphenopalatine foramen, which is usually enlarged. •• Endovascular and surgical therapies are the mainstays of treatment. These lesions, although benign, can be locally aggressive with high rates of recurrence.

■■ Other Imaging Findings •• MRI can also demonstrate the full extent of the tumor, particularly with regard to intracranial extension. •• Angiography can be both diagnostic as well as therapeutic. Lesion is typically supplied by the internal maxillary branch of the external carotid artery.

�Pearls & � Pitfalls ÛÛ In an adolescent boy, with a lesion at this location, JNA must be excluded.

ÚÚ Conversely, if such a lesion is noted, biopsy must not be performed, as the risk of uncontrollable hemorrhage is high. ÚÚ If a JNA is found in a young woman, genetic testing is probably warranted.

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Case 10

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■■ Clinical Presentation A 61-year-old woman presents with continuous tone in the right ear, which was not tinnitus. She also has mild highfrequency sensorineural hearing loss.

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20/05/16 10:55 AM

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■■ Imaging Findings

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(A–D) A dumbbell-shaped fusiform posterior fossa mass extending from the retro-olivary sulcus of the medulla into the jugular fossa exhibits low T1 signal and high T2 signal (arrow). The mass enhances intensely (arrow) on postcontrast images.

■■ Differential Diagnosis •• Jugular foramen schwannoma: Well-circumscribed tubular low T1 signal and high T2 signal intensely enhancing mass arising from the retro-olivary medullary groove along the course of cranial nerves IX to XI is seen extending into an enlarged jugular fossa without high velocity flow voids. •• Glomus jugulare paraganglioma: Jugular fossa mass with permeative destructive bone changes along the margins of jugular fossa on CT, erosion of jugular spine, and presence of flow voids on MRI. •• Jugular foramen meningioma: Permeative/hyperostotic bony changes are seen on CT and dural tail on MRI. •• Vestibular schwannoma: Intensely enhancing mass arising from brainstem extends toward and into the internal acoustic canal (IAC) on MRI. It is centered higher than jugular fossa schwannoma. On CT, the bony changes are confined to the IAC.

■■ Essential Facts •• Arises from Schwann cells in cranial nerves IX to XI into the jugular fossa and into the nasopharyngeal carotid space; most commonly arising from cranial nerve IX. •• Second most common soft tissue mass of the jugular fossa, following paraganglioma. Multiplicity of schwannomas is associated with neurofibromatosis type 2 (NF2) and associated with a chromosome 22 defect. •• Slow-growing mass with most common clinical presentation of sensorineural hearing loss. Cranial nerve IX to XI neuropathy is a late presentation. Clinically and radiologically, it may be confused with vestibular schwannoma.

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•• Does not have intratumoral necrosis but can have areas of cysts and hemorrhage related to differential composition of Antoni A and B cells. •• Treated with surgical removal. Injury to cranial nerves VII to XII is known surgical sequelae.

■■ Other Imaging Findings •• On CT, a fusiform densely enhancing hypodense mass is seen extending into the jugular fossa, which shows smooth with sclerotic rim but no permeative, erosive changes. On coronal reconstruction, amputation of “bird’s beak” is described. •• On MR, low T1 and high T2 signal, tubular mass arising from expected location of cranial nerves IX to XI (retroolivary groove of medulla) with intense postcontrast enhancement is seen extending into the jugular fossa and then into the carotid spaces of the nasopharynx. •• On angiography, the tumor is only moderately vascular without any significant tumor blush. The feeding vessels are tortuous without significant enlargement of any feeding artery. Scattered contrast puddles may be seen.

�Pearls & � Pitfalls ÛÛ A tubular well-circumscribed well-enhancing fusiform mass arising from retro-olivary grove of the medulla extending into the jugular fossa with smooth enlargement without any permeative/hyperostotic changes that does not show any high velocity flow voids. ÚÚ Clinically and radiologically, it can be mixed with vestibular schwannoma.

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Case 11

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■■ Clinical Presentation A 33-year-old woman presents with bulging eyes.

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(A) Axial noncontrast CT image of the orbits demonstrates bilateral exophthalmos. (B) Coronal reformat shows diffuse enlargement of the extraocular muscles bilaterally, particularly involving the inferior recti (arrowheads). Lower attenuation is noted centrally within the muscle belly (arrow).

■■ Differential Diagnosis

•• Later phase of the disease may demonstrate muscle thinning with prominence of the intraorbital fat. •• Assessment of the orbital apex should be performed to look for crowding and encroachment upon the optic nerve (which may require surgical decompression).

•• Thyroid orbitopathy (Graves disease): In a patient presenting with painless proptosis involving both orbits and enlargement of bilateral extraocular muscles, this is the most likely diagnosis. •• Orbital pseudotumor: Less likely, given findings. Pseudotumor typically results in pain and is unilateral. Radiographically, there can be muscular enlargement, although the tendon insertion may be involved as well. •• Cavernous sinus fistula: May also result in bilateral exophthalmos. However, on CT, there is usually enlargement of the superior ophthalmic vein.

■■ Other Imaging Findings

■■ Essential Findings

�Pearls & � Pitfalls

•• Thyroid orbitopathy is a thyroid-associated process that results in mucopolysaccharide deposition within the extraocular muscles resulting in early enlargement of the muscle, with relative sparing of the tendon. •• Mucopolysaccharide deposition may result in relative low attenuation centers of the muscles involved. •• Muscular involvement typically follows the temporal pattern of IMSLO, where the inferior rectus is most frequently affected, followed by the medial, superior, and lateral recti, and least frequently, the oblique muscles.

ÛÛ In a patient with bilateral painless enlargement of the

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•• CT is useful for diagnosis and in presurgical planning to assess the bony anatomy. •• MRI demonstrates similar findings to CT but lacks osseous detail.

extraocular muscles, Graves disease is the most likely diagnosis. ÚÚ Tendinous involvement can rarely also be seen with Graves orbitopathy, causing a radiographic appearance similar to pseudotumor. � Other causes of myositis/myopathy can include systemic diseases (such as Wegener granulomatosis, sarcoidosis), lymphoma, and metastatic disease.

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Case 12

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■■ Clinical Presentation Unrelated symptoms. In this case, a 19-year-old complains of tremors in bilateral hands. Head CT reveals presence of an opacified left petrous apex.

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■■ Differential Diagnosis •• Petrous apex fluid collection: Asymptomatic lesion with opacification of the petrous apex is seen without evidence for expansion or infection on CT. Low to intermediate T1 signal and high T2 signal without impeded diffusion is seen on MR. •• Cholesterol granuloma of petrous apex: Expansile lesion on CT is seen with thinning of the cortical margin. High T1 and high T2 signal lesion in the petrous apex. •• Congenital cholesteatoma petrous apex: Smooth in expansile lesion of the petrous apex on CT exhibits a rim enhancement on postcontrast MRI. •• Mucocele of petrous apex: Expansile lesion of the petrous apex with low T1 MR signal and rim enhancement on postcontrast MRI.

E

(A) Bone window for dedicated temporal bone CT reveals soft tissue opacification of left petrous apex (arrow) without undue expansion. (B) Diffusion-weighted MRI does not reveal any focal area of restricted diffusion. (C) T1-weighted MRI reveals mildly high T1 signal (arrow). (D) T2-weighted MRI reveals high T2 signal area at left petrous apex (arrow). (E) No significant contrast enhancement is seen following intravenous gadolinium administration (arrow).

•• It is postulated that intermediate or high T1 signal lesions may transform in future into a cholesterol granuloma.

■■ Other Imaging Findings •• On CT, unilaterally opacified petrous apex air cells are seen without trabecular loss. There is no evidence for middle ear or mastoid inflammatory changes. The margins of the air cells may be sclerotic from previous infection without evidence for expansion or destruction. •• On MRI, low to intermediate T1 and high T2 signal fluid is seen without significant postcontrast enhancement. The high T1 signal is attributed to protein content.

�Pearls & � Pitfalls ■■ Essential Facts •• The patient is generally asymptomatic and undergoing cross-sectional examination for other reasons. •• It remains unchanged throughout the life span. •• No treatment or follow-up is required. •• Residual fluid in the petrous apex air cells is found in ~1% of all head MR. It likely represents stabile residual fluid from remote infection.

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ÛÛ Asymptomatic unilateral opacification of the petrous

apex air cells in absence of inflammatory changes on CT with low to intermediate T1 and high T2 signal without restricted diffusion on MRI. ÚÚ Differentiation from cholesterol granuloma or apical petrositis can save unnecessary surgical intervention.

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Case 13

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■■ Clinical Presentation A 37-year-old woman presents with malaise and multiple neck lumps.

■■ Further Work-up

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■■ Imaging Findings

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(A) Contrast-enhanced CT of the neck demonstrates a ring-enhancing lesion within the posterior paraspinal neck musculature on the right (arrowhead). (B) Multiple lung nodules are noted on the chest CT.

■■ Differential Diagnosis •• Lymphoma: In an adult patient with a ring-enhancing lesion, systemic symptoms, and other radiographic findings, neoplasias (e.g., metastases or lymphoma) should be strongly considered. •• Abscess: Similarly, an infectious process could result in the formation of local abscesses or necrotic lymph nodes. Atypical infectious agents would be more likely to produce the more protean symptoms noted in this patient. •• Venolymphatic malformation: Would be a radiographic consideration in a child or young adult if isolated to the neck. No systemic symptoms would be expected, and chest findings would not be present on radiographic studies.

may present with nodal enlargement. Histologic evaluation is always required.

■■ Other Imaging Findings •• CT scans of the chest, abdomen, and pelvis are standard of care for staging purposes to define the full extent of disease radiographically. Note that nonenlarged (, 1 cm), necrotic nodes may also harbor disease. •• Gallium-67 citrate has been used to determine the disease status of residual soft tissue masses. •• FDG-PET scanning has emerged as a new modality to determine disease status with greater resolution, particularly in combination with CT performed at the same time.

■■ Essential Facts

�Pearls & � Pitfalls

•• One of the great mimickers of radiology, lymphoma can take on several radiographic appearances, depending on the histology and involved organ system. •• Lymphomas are divided into two major categories, Hodgkin lymphoma and non-Hodgkin lymphoma (NHL), based on the presence of Reed-Sternberg cells. •• Hodgkin disease of the head and neck typically manifests as nodal enlargement on radiographic exams. Involved nodes are usually enlarged (. 1 cm) and homogeneous. •• NHL also presents with nodal involvement but may also be found within extranodal sites. •• Necrotic nodes are seen less commonly in lymphoma but can be noted in patients who have been previously treated. Any necrotic node, however, even if , 1 cm, must be treated with suspicion. •• Note that metastatic lesions from other primary tumors

ÛÛ Ring-enhancing lesions within the neck are generally

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seen with infection, neoplasia, or congenital malformations. ÚÚ Proper radiographic staging of lymphoma requires CTs of the chest, abdomen, pelvis, and neck. Head imaging may also be required, if neurologic symptoms are present. ÚÚ FDG-PET may demonstrate nonenlarged diseased nodes that do not appear suspicious on traditional anatomic exams (MR/CT). ÚÚ Any necrotic node, whatever the size, must be treated with the suspicion of disease involvement. ÚÚ Tissue diagnosis is ultimately required for most ringenhancing head and neck lesions because, as noted, many entities can have a similar appearance.

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Case 14

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■■ Clinical Presentation A 15-year-old presents with retro-orbital pain.

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20/05/16 11:01 AM

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■■ Differential Diagnosis •• Petrous apicitis: Opacification of petrous air cells with trabecular erosion is seen on CT. On MRI, low to intermediate T1 signal and high T2 signal reveals presence of proteinaceous fluid that exhibits patchy and peripheral rim enhancement along with enhancement of the adjacent meninges. •• Trapped fluid of petrous apex: There is lack of cortical expansion with presence of fluid at the petrous apex. No significant postcontrast enhancement is seen on MRI with lack of meningeal enhancement and lack of impeded diffusion. •• Congenital cholesteatoma of petrous apex: Smooth expansile petrous apex mass is seen on CT. MRI reveals low T1 signal with lack of meningeal enhancement. •• Cholesterol granuloma of petrous apex: Expansile petrous apex mass with trabecular destruction and thinning of overlying cortex is seen on CT. High T1 and high T2 signal is seen on MRI. •• Primary or secondary malignant lesion of petrous apex: Permeative/destructive mass of petrous apex is seen on CT. There may be involvement of the adjacent petroclival suture or clivus. There is lack of acute onset infectious symptoms.

■■ Essential Facts •• Acute or chronic otomastoiditis can spread matter generously by venous channels or by direct extension through air cells to the petrous apex. •• Generally seen in pediatric age group following acute otomastoiditis. •• Most common presentation is retro-orbital pain and ear pain. Acute palsy of cranial nerves VI or V is not uncommon.

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(A) CT scan of temporal bone reveals opacification of the right petrous apex (arrow) with rarefaction of the trabeculae without expansile changes. (B) Diffusion-weighted MRI reveals an area of impeded diffusion (arrow) at the right petrous apex. (C) T1-weighted MRI reveals low to intermediate T1 signal (arrow) at the right petrous apex. (D) T2-weighted MRI reveals high T2 signal (arrow) at the right petrous apex. (E) Peripheral rim and patchy enhancement of the right petrous apex lesion (arrow) is seen following intravenous gadolinium contrast with mild enhancement of the adjacent meninges.

•• Clinical triad of otomastoiditis, deep facial pain, and cranial nerve VI palsy with petrous apicitis is known as Gradenigo syndrome. •• It is becoming rare in this era of antibiotics; however, if untreated, it can lead to meningeal infection and spread to Meckel’s cave and cavernous sinus with obtundation and death. •• Treatment is aggressive surgical intervention with mastoidectomy and drainage along with intravenous antibiotics.

■■ Other Image Findings •• On CT, there is opacification of the petrous apex with erosion of the trabeculae and possible confluent apical air cells. In the late stage, erosion of the cortical margins with extension of the inflammation to adjacent meninges leading to meningitis is also seen. There may be a history of recent otomastoiditis or simultaneous middle ear and mastoid infection. •• On MRI, low to intermediate T1 and high T2 signal is visualized. Impeded diffusion is diagnostic. On postcontrast study, rim-enhancing fluid within the petrous apex with enhancement of the adjacent meninges is seen. There may be involvement of cavernous sinus or Meckel’s cave depending on the extent of spread.

�Pearls & � Pitfalls ÛÛ Confluent opacification of the petrous apex with erosion of trabeculae is seen on CT. Impeded diffusion and rimenhancing fluid in the petrous apex with enhancement of the adjacent meninges is a characteristic MRI finding. ÚÚ Inadequate diagnoses resulting in lack of treatment can result in significant morbidity and mortality.

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Case 15

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■■ Clinical Presentation A 6-month-old infant presents with an abnormal eye exam.

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■■ Imaging Findings

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(A, B) Contrast-enhanced orbital CT shows a partially calcified soft tissue lesion along the posterior aspect of the right optic globe (arrow).

■■ Differential Diagnosis •• Retinoblastoma (Rb): In an infant with a soft tissue, partially calcified mass within the optic globe, this is the most likely diagnosis. •• Coats disease: Usually not seen in the infant population and typically does not calcify unless advanced. Imaging features are typically those of retinal detachment due to effusions, but this lesion may be difficult to differentiate from Rb. •• Persistent hyperplastic primary vitreous: Typically presents with microphthalmos and does not calcify. Tubular tissue within the globe may suggest this diagnosis.

■■ Essential Facts •• Retinoblastoma is the most common intraocular tumor of young children. •• Microscopically, tumor cells appear similar to retinoblasts found in the embryonic retina—hence the name. •• Clinically, patients can present with leukokoria, strabismus, or glaucoma. •• On orbital CT, a soft tissue mass is typically noted. Associated calcifications are present in 70% of cases and strongly suggest the diagnosis.

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•• MRI better demonstrates the lesion, especially if the tumor is not calcified. Rbs typically demonstrate T2 hypointensity, thus helping in differentiating these lesions from benign disease processes. •• MRI can also demonstrate extraglobal spread of tumor as well as any evidence of additional tumors within the contralateral globe (bilateral), the suprasellar region (trilateral), or pineal region (quadrilateral).

■■ Other Image Findings •• MRI demonstrates slight T1 hyperintensity of the tumor with low T2 signal and some degree of contrast enhancement.

� Pearls & � Pitfalls ÛÛ Most common intraocular tumor of young children. ÚÚ CT may not show the calcification in all cases, MRI can be particularly helpful in such patients.

ÚÚ On imaging, look for additional potential sites of disease such as the contralateral globe, the suprasellar cistern, and pineal regions, as additional tumors will change treatment strategies.

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Case 16

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■■ Clinical Presentation A 7-year-old presents with right-sided proptosis of sudden onset.

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■■ Imaging Findings

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(A, B) MRI of the brain reveals a predominantly intraconal lobulated multilocular mass with a fluid–fluid level (arrow) characteristic of sequelae of prior hemorrhage. Sagittal and fat saturated T1-weighted axial imaging reveals the multilocular mass (arrow) in the left extraconal spaces with medial and superior displacement of the right optic nerve and proptosis of the right orbital globe which is mildly flattened posteriorly. (C) T2-weighted axial image also reveals a loculated mass (arrow) and a presence of a tubular high T2 signal complement at the medial part of right intraconal spaces, compatible with lymphatic channels. (D) Post–gadolinium contrast T1 axial image does not reveal any significant enhancement (arrow).

■■ Differential Diagnosis •• Lymphatic malformation of orbit: An irregular multiloculated cystic mass seen in pediatric population with irregular margins, multiple cystic regions, and propensity to hemorrhage with fluid–fluid level without significant postcontrast enhancement. •• Venolymphatic malformation of orbit: Lobulated irregular transpatial mass seen in pediatric population with blood and fluid levels and heterogeneous postcontrast enhancement. •• Capillary hemangioma of orbit: Intensely enhancing vascular mass of pediatric population that is a proliferative mass and not malformation. Often regresses spontaneously. •• Cavernous hemangioma of orbit: Well-demarcated ovoid intraconal mass in adult population with a characteristic low flow arteriovenous malformation (AVM) with patchy enhancement. Hemorrhage and phleboliths are unusual in orbit. •• Venous varix of orbit: An enlarged venous channel with systemic connection that can distend with Valsalva maneuver.

■■ Essential Facts •• It is a congenital, benign, vascular malformation composed of multiple dilated lymphatic endothelial channels that are not connected with systemic vascular or lymphatic systems. Also known as lymphangioma and cystic hygroma. •• It usually presents in the first decade and does not involute unlike an orbital capillary hemangioma and may be associated with known lymphatic malformations or venolymphatic malformations in the face, eyelids, oral cavity, or other head and neck spaces.

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•• Most common presentation is intermittent proptosis. Ptosis, diplopia, periorbital ecchymosis, optic nerve compression, and restricted movement of the orbital globes may be present. •• The cysts usually contain blood and serous fluid, and the lesion may spontaneously increase in caliber with acute hemorrhage. •• Total surgical resection is difficult due to complex irregular shape of the mass that interleaves with normal orbital tissue. Systemic steroids help to reduce the size of the mass and resultant proptosis.

■■ Other Imaging Findings •• On CT, an intraconal or extraconal multicystic, multilocular heterogeneous mass with irregular margins is seen. It is mildly hyperattenuating compared with muscles and is seen across multiple anatomic compartments. Mild bony remodeling is possible. •• On MRI, fluid–fluid levels of hemorrhage are seen within the enlarged cystic spaces. Different ages of hemorrhage may be seen. Signal intensity is heterogeneous with variable low to high T1 signal and low to high T2 signal. It does not increase in size with Valsalva maneuver.

� Pearls & � Pitfalls ÛÛ Multiloculated, multicystic nonenhancing mass with

fluid–fluid levels of hemorrhage in infancy or early childhood with proptosis and restricted eye movements. ÚÚ It does not involute spontaneously and does not increase in size with Valsalva maneuver. This allows it to differentiate from capillary hemangioma and venous varix.

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Case 17

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■■ Clinical Presentation A 38-year-old woman presents with neck pain and fever.

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(A, B) Axial contrast-enhanced CT scan of the neck was obtained. There are multiple rim-enhancing collections in the retropharyngeal/prevertebral spaces (arrows) with posterior extension into the anterior epidural space of the spinal canal (arrowhead).

■■ Differential Diagnosis •• Prevertebral/retropharyngeal abscess: Given the clinical scenario and the findings of rim-enhancing fluid collection(s), this is the most likely diagnosis. •• Reactive effusion: Could have some similar clinical features, such as pain. However, there is lack of rim enhancement in such collections. •• Hematoma/seroma: Not congruent with the clinical setting. Additionally, our process appears transpatial, involving the prevertebral and epidural spaces.

■■ Essential Facts •• Retropharyngeal and prevertebral spaces of the neck abut one another. Often, it is radiographically impossible to distinguish one space from the other, and thus, these spaces are often discussed together. •• Infection of the retropharyngeal space can be seen with direct inoculation or as a result of lymphatic drainage from more superior areas. Prevertebral infections are often the result of prior intervention or cervical spondylodiskitis.

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•• Patients present with a variety of symptoms and usually appear quite ill. Cross-sectional imaging may demonstrate the early stage of soft tissue induration without a drainable fluid collection. Such patients often can be managed conservatively. •• Conversely, rim-enhancing fluid collections and those involving the epidural space are usually surgically drained.

� Pearls & � Pitfalls ÛÛ Infections of the prevertebral/retropharyngeal spaces

should prompt evaluation as inferiorly as possible, as extension into the mediastinum may occur. ÚÚ Non–rim-enhancing effusions can be seen in a variety of settings (prior radiation treatment, SVC occlusion, calcific tendinitis) and are not treated surgically. ÚÚ Retropharyngeal lymph nodes may suppurate when there is adjacent pharyngitis or become necrotic in malignancy and can appear as small (, 1 cm) ovoid fluid collections in these areas. Clinical correlation is thus often necessary.

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Case 18

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■■ Clinical Presentation A 54-year-old presents with incidental finding of sinonasal mass in the CT ordered for a syncopal episode.

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(A) CT scan of the head shows diffuse opacification of the frontal and ethmoidal sinuses with remodeling of the bony walls with cortical erosion (arrow) of the superior part of the right lamina papyracea. (B) T1-weighted axial image reveals high T1 signal (arrow) at right frontal sinus. The left frontal sinus is not pneumatized. (C) FLAIR-weighted axial image reveals high T2 signal (arrow) at right frontal sinus. (D) Postcontrast T1-weighted imaging does not reveal any abnormal postcontrast enhancement (arrow) of the sinus lesion.

■■ Differential Diagnosis •• Sinonasal mucocele: Low-density expansile mass of the right frontal ethmoidal sinus with remodeling of the bony wall and focal thinning of the right lamina papyracea. High T1 and T2 signals indicate high protein content of the mucus. •• Acute sinusitis: Normal-sized sinus lumen with mucosal thickening and areas of air–fluid levels. Odontogenic source may be suspected if the isolated maxillary sinus is involved. •• Chronic sinusitis: Mucosal thickening with possible obstructing lesions in drainage pathways. Areas of irregular bone sclerosis and thickening of the sinus wall may be seen. •• Sinonasal polyposis: Lobular soft tissue masses with opacification and possible expansion of paranasal sinuses. Involves both the nasal cavity and sinuses in the background of allergy. •• Inverted papilloma: Lobular mass in nasal cavity involving the middle meatus with extension into the maxillary antrum reveals heterogeneous matrix and intense contrast enhancement. •• Fungal sinusitis: Opacified sinuses with remodeling may have low T2 signal, which may be as dark as the air. Areas of calcification may be seen on CT. Some degree of contrast enhancement is almost always seen. •• Benign or malignant sinonasal neoplasm: Somewhat irregular and expansile soft tissue masses may cause remodeling of the sinus walls but almost always enhance on postcontrast imaging.

■■ Essential Facts •• A largely clinically silent mucus-containing expansile lesion of the paranasal sinuses with secondary obstruction of the main ostium of the affected paranasal sinus. •• The lesion is lined by ciliated columnar respiratory epithelium.

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•• It becomes symptomatic only when it extends into surrounding tissue planes secondary to remodeling of the surrounding bone and erosion. •• Most common sinus involvement is frontal (67%), followed by ethmoidal (20%), maxillary (10%), and sphenoidal (3%). •• Total surgical resection can result in complete cure.

■■ Other Imaging Findings •• CT scan of the paranasal sinuses reveals a low attenuating expansile lobulated mass with smooth margins within a paranasal sinus with remodeling of bony walls of the sinus. There may be focal thinning and erosion of the bony wall if imaged when the patient is symptomatic. No abnormal postcontrast enhancement is seen. •• MRI may reveal low T1 signal due to high water content or high T1 signal due to proteinaceous content. The T2 signal may be high or low, depending on the degree of inspissation. No significant postcontrast enhancement is seen. If detected early, low T1 and high T2 signal within a lobulated mass is seen due to high water content.

� Pearls & � Pitfalls ÛÛ Early mucocele reveals high water content with low T1

and high T2 signal. However, at this stage, it is generally asymptomatic. ÛÛ A mucocele becomes symptomatic when it extends into adjacent compartment secondary to erosion of the wall. Due to chronic inspissation, it generally reveals high T1 and variable low to high T2 signal at this stage. ÛÛ If first detected on MRI with low T2 and high T1 signal, a CT scan should be performed to confirm the diagnosis and rule out other aggressive conditions. ÚÚ Benign or malignant masses of paranasal sinuses almost always enhance on postcontrast imaging.

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Case 19

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■■ Clinical Presentation A 7-year-old girl presents with a neck lump.

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■■ Imaging Findings

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(A–C) MRI was obtained, including axial T1 (A), T2 with fat saturation (B), and T1 postcontrast with fat saturation (C). There is a septated mass lesion along the left aspect of the neck, just posterior to the sternocleidomastoid muscle (arrows). The lesion demonstrates multiple cystic foci of T2 prolongation with primarily septal enhancement.

■■ Differential Diagnosis

■■ Other Imaging Findings

•• Venolymphatic malformation (VLM): This is at the top of the differential list due to the patient’s age and radiographic findings of multiple septations and lack of much solid enhancement. •• Branchial cleft cyst: If this lesion were unilocular and ran across the anterior margin of the sternocleidomastoid muscle, it could appear quite similar to a VLM. •• Necrotic lymph node: Again, a necrotic lymph node could appear similar.

•• VLMs can have a variety of MRI appearances based on the amount of venous or lymphatic tissue present. •• Lymphatic, cystic areas demonstrate extensive T2 prolongation with peripheral enhancement. Fluid–fluid levels can be seen in such lesions. •• Lesions that contain more venous elements may enhance in a more solid fashion and may demonstrate calcified phleboliths. •• VLMs can be transpatial (in comparison to many other lesions of the head and neck), which can further suggest the diagnosis.

■■ Essential Facts •• VLMs are congenital “slow flow” lesions consisting of various amounts of venous and lymphatic tissue. If primarily lymphatic, it is often referred to as cystic hygromas. •• These lesions may go unnoticed clinically for a long time, if small, until trauma or infection may cause some degree of enlargement. •• Therapy for VLMs can include a combination of sclerotherapy and/or surgical intervention.

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� Pearls & � Pitfalls ÛÛ VLMs can be transpatial, suggesting the diagnosis. ÚÚ Although benign, such lesions can grow and should be referred to appropriate specialty care.

ÚÚ Rarely, other more aggressive lesions can have a similar appearance.

ÚÚ Mapping out of the full extent of the lesion is necessary if surgical resection is to be performed.

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Case 20

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■■ Clinical Presentation A 57-year-old presents with monocular diplopia, dryness of the eye, and progressive painful proptosis of the right eye.

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■■ Imaging Findings

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■■ Differential Diagnosis •• Orbital pseudotumor: Infiltrating, intraconal, retroorbital, nongranulomatous mass, usually unilateral and involving extraocular musculature, including tendinous portion in patient with painful proptosis. Intense postcontrast enhancement, based on evaluated fatsuppressed postgadolinium T1-weighted MRI. It is possible to have only muscular involvement; however, the tendinous portion is always involved. •• Thyroid ophthalmopathy: It is the most common cause of proptosis in adults. However, 80% of the cases have bilateral involvement, and more than 90% patients are hyperthyroid. The enlargement of extraorbital muscles does not extend into tendinous portion. •• Orbital cellulitis: Generally secondary to adjacent sinusitis or trauma. There is phlegmonous periorbital and intraconal infiltration and may be associated with a subperiosteal abscess. •• Lymphoproliferative lesions of orbit: A wide variety of diseases from lymphoid hyperplasia to non-Hodgkin lymphoma. A solid enhancing mass or infiltration, most commonly extraconal; may involve the lacrimal gland. •• Sarcoidosis: Twenty percent of patients with systemic disease have orbital involvement. Granulomatous enhancement of multiple orbital structures is seen, most commonly in the lacrimal gland.

■■ Essential Facts •• Nongranulomatous mixed inflammatory infiltrate of any area of the orbit which is idiopathic and nonspecific. It can mimic multiple orbital pathologies. •• After Graves disease and lymphoma, it is the third most common orbital mass. Histologically, it is a mix of inflammatory infiltrate and fibrosis. •• Most common clinical presentation is painful proptosis, redness of eye, and visual disturbances. It is usually unilateral, with only 25% of the cases having bilateral disease. •• Predominantly intraconal location but almost always involves extraorbital muscles. Involvement of tendinous

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(A) Coronal noncontrast CT shows an infiltrating intraconal retrobulbar mass (arrow) involving the superior and lateral rectus muscle. (B) T1-weighted sagittal MRI reveals infiltrating retrobulbar low T1 signal mass (arrow) involving the superior rectus muscle. (C) T2-weighted coronal MRI reveals patchily high T2 signal intraconal mass (arrow) involving expanded superior rectus and lateral rectus muscles. (D, E) Postcontrast fat-suppressed T1-weighted image reveals infiltrative intensely enhancing intraconal retro-orbital mass (arrow) involving the superior and lateral rectus muscles.

insertion differentiates it from thyroid ophthalmopathy, which spares the tendinous portion of extraorbital muscles. The lacrimal gland, uvea, sclera, optic nerve sheath, and bony orbits can be variably involved. •• Treatment consists of high-dose steroids. In resistant cases, radiotherapy, chemotherapy, and decompressive surgery may be performed.

■■ Other Imaging Findings •• On CT scan, an infiltrating retrobulbar soft tissue mass can be seen with involvement of extraorbital musculature. When involved, the expansion of muscle also extends into tendinous insertions. It is possible to have involvement of only single or multiple orbital muscles without infiltrating conal mass. •• On MRI, infiltrating low T1 signal retrobulbar mass appears hyperintense on T2-weighted images and exhibits intense postcontrast enhancement. Postcontrast fat-suppressed T1-weighted imaging is most helpful for diagnosis. •• Depending on location, it is categorized as myositic (only involves extraocular muscles), lacrimal, anterior (retrobulbar and/or orbital globe), apical (orbital apex), or diffuse (multifocal intraconal and extraconal).

� Pearls & � Pitfalls ÛÛ Irregular and infiltrating mass–like intensely enhanc-

ing soft tissue lesion that involves any area of orbit. Clinically, painful proptosis is almost always present as opposed to Graves disease which can be without pain. Unilateral involvement is more common, and enlargement of extraorbital muscles extends into tendinous portion, unlike Graves disease. It is helpful to rule out a carotid-cavernous fistula which can have a similar clinical presentation but very different imaging appearance. ÚÚ Sometimes it is difficult to differentiate from lymphoproliferative disease, especially non-Hodgkin lymphoma. Biopsy may be required for patients who do not respond to high-dose steroids.

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Case 21

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■■ Clinical Presentation A 68-year-old woman presents with voice changes.

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■■ Imaging Findings

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(A–D) Axial contrast-enhanced CT images were obtained through the larynx in soft tissue (A, B) and bone (C, D) algorithms. There is an expansile calcified lesion involving the left thyroid lamina with a chondroid type of matrix (arrowheads).

■■ Differential Diagnosis •• Chondrosarcoma: A calcified lesion of the laryngeal cartilage, particularly with this type of matrix, should be considered a chondroid-type lesion. •• Squamous cell carcinoma: Most common neoplasm of the larynx. However, these lesions do not calcify and are centered within the glottic, subglottic, or supraglottic mucosa. •• Metastasis: Rare to develop within the laryngeal structures. May cause expansion of the cartilage, typically without an internal calcified matrix.

■■ Essential Facts •• Rarest (, 1%) of all laryngeal tumors. Tumors can arise from any cartilaginous structure of the larynx, particularly the cricoid and thyroid cartilages. •• These are neoplasms of the chondroid structures, which typically behave in an indolent manner. •• Patient complaints vary based on the location of the tumor and include neck masses, hoarseness, and vocal cord paralysis.

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•• As in other areas of the body, benign chondroid lesions can have a similar appearance radiographically, and pathological examination is necessary to determine the histological diagnosis.

■■ Other Imaging Findings •• MRI may demonstrate signal voids from the calcifications with enhancement of soft tissue components.

� Pearls & � Pitfalls ÛÛ Expansile lesion of the laryngeal cartilage with chon-

droid calcification can suggest a specific diagnosis of chondrosarcoma. ÚÚ If calcification is not noted, include other entities such as metastasis, lymphoma, and even plasmacytoma within the differential. ÚÚ Mapping out tumor extent is critical for surgical resection.

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Case 22

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■■ Clinical Presentation A 46-year-old woman presents with hemifacial spasm, hearing loss, and ear pain.

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■■ Imaging Findings

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(A–D) A low to intermediate T1 signal and intermediate to high T2 signal irregular mass (arrow) exhibits intense postcontrast enhancement within the left internal auditory canal (IAC), extending into the labyrinthine canal.

■■ Differential Diagnosis •• Facial nerve schwannoma: Intensely enhancing intermediate T1 and high T2 signal mass within the IAC, extending into the labyrinthine canal at the expected location of the geniculate ganglion. •• Facial nerve hemangioma: Irregular enhancing mass, most likely at the geniculate ganglion with heterogeneous T2 signal that can exhibit foci of calcification on CT scan. •• Congenital cholesteatoma: Nonenhancing irregular low T1 and intermediate to high T2 signal mass extending from the petrous apex along the facial nerve canal.

■■ Essential Facts •• Slow-growing, rare, benign neoplasm arising from the outer nerve sheath layer formed by Schwann cells along the facial nerve. •• Most common clinical presentation is slowly progressive facial nerve weakness and heading loss. •• Tympanic or mastoid segment facial nerve tumor presents with conductive hearing loss. When located within the IAC, presentation is vertigo, tinnitus, and sensorineural hearing loss. Other symptoms include hemifacial spasm, Bell palsy, or ear pain.

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•• Surgical resection may not fully restore facial nerve function. Preservation of facial nerve function and hearing along with complete removal are goals of surgery.

■■ Other Imaging Findings •• On CT scan, there is enlargement and remodeling of the facial nerve canal around its location. •• Intermediate to low T1 and high T2 signal intensely enhancing rounded or tubular mass along the expected course of the facial nerve is seen on MRI. The most common location is in the geniculate ganglion area.

� Pearls & � Pitfalls ÛÛ Bony enlargement of facial nerve canal on CT and

intensely enhancing high T2 signal soft tissue mass on MRI in a patient with slowly progressive facial nerve palsy and hearing loss are characteristic findings. ÚÚ A vestibular schwannoma can mimic the appearance if located only within the cerebellopontine angle (CPA) or IAC. Look for enlargement of the fallopian canal or subtle enhancement into the labyrinthine segment if clinical picture favors facial nerve schwannoma.

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Case 23

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■■ Clinical Presentation A 9-year-old girl presents with fullness of the left eye.

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■■ Imaging Findings

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(A–C) Axial contrast-enhanced CT images of the orbits in bone (A) and soft tissue algorithms (B) show a small, round, well-circumscribed lesion along the medial canthus of the left orbit (arrow). The lesion is of fat attenuation (C). No adjacent osseous changes are identified and there is little opacification of the adjacent left ethmoid sinuses.

■■ Differential Diagnosis •• Orbital dermoid: In a pediatric patient, a fat-attenuated well-circumscribed lesion is most likely to represent an orbital dermoid, particularly if there is no adjacent osseous erosion. •• Orbital tumor: Primary or secondary orbital tumors are more likely to have soft tissue components. Adipose containing malignant lesions in this location are rare. •• Subperiosteal abscess: Given the lack of adjacent inflammatory changes within the paranasal sinuses and patient history, this is not a likely diagnosis. Most such lesions are crescentic and located in direct continuity with the medial orbital wall.

■■ Essential Facts •• Orbital dermoids are benign congenital lesions that grow slowly over time. •• Most commonly, they arise along the superotemporal aspect of the orbit and are often found along suture lines. Adjacent smooth osseous remodeling may occur. •• Attenuation value measurements are helpful in making the diagnosis on CT. Such lesions measure either fluid

Case_023_045-046.indd 46

(epidermoid) or fat attenuation, are well circumscribed, and may contain calcification or fat–fluid levels. Dermoids should not enhance centrally; however, peripheral enhancement may occur.

■■ Other Imaging Findings •• On MRI, dermoids should reveal fat signal intensity without appreciable enhancement. Epidermoids will demonstrate T1 prolongation (low T1 signal) and may restrict diffusion. Again, peripheral, but not central, enhancement may be seen.

� Pearls & � Pitfalls ÛÛ Rupture of an orbital dermoid may result in extensive

inflammatory changes, sometimes making the diagnosis difficult. ÚÚ Full extent of the lesion must be evaluated on imaging prior to surgical planning.

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Case 24

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■■ Clinical Presentation A 50-year-old man with a history of smoking presents with a 40-year history of right-sided nasal obstruction.

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■■ Imaging Findings

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(A–C) CT scan of the maxillary sinus shows an expansile locally aggressive sinonasal mass causing extensive bony remodeling without destructive erosive changes extending from the maxillary antrum to nasal cavity (long arrow) to nasopharyngeal masticator spaces (short arrow). Trapped bone is visualized within the mass. (D–F) Low T1 and intermediate to heterogeneous linear high T2 signal mass (black arrow) also exhibits patchy heterogeneous postcontrast enhancement.

■■ Differential Diagnosis •• Inverted papilloma: Locally aggressive expansile mass with extensive remodeling on CT without bone destruction, presence of trapped bones, and unilateral sinus opacification. •• Antrochoanal polyp: Cystic, high T2 signal nonenhancing dumbbell-shaped mass extending across the ostiomeatal unit from the maxillary antrum to the nasal cavity. •• Sinonasal polyposis: Generally bilateral distribution with history of allergies. Benign masses with bony remodeling. •• Malignant sinonasal masses like squamous cell carcinoma: Originates within the maxillary sinus rather than nasal cavity and is seen in middle-age group males. Irregular poorly defined mass with aggressive bone destruction and heterogeneous enhancement.

■■ Essential Facts •• Benign but locally aggressive expansile epithelial sinonasal tumor in which the tumor epithelium inverts into the underlying matrix of the lateral nasal wall with endophytic growth pattern. It has a malignant potential and may be synchronous or metachronous with squamous cell carcinoma. •• Predominantly seen in middle to elderly age group with male dominance. •• Most common presentation is sinusitis. Other symptoms include nasal obstruction, nasal discharge, and epistaxis.

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•• Surgical resection is treatment of choice. However, it has a high recurrence rate of 20 to 30%.

■■ Other Imaging Findings •• On CT scan, the lobulated aggressive mass centered in the medial meatus region extends into the maxillary sinus with obstruction of the ostiomeatal complex. When larger, it causes remodeling of the nasal cavity and maxillary sinus and may cause secondary opacification of the frontal, ethmoidal, and sphenoidal sinuses due to obstruction. Due to remodeling, a trapped bone is seen frequently along with tumoral microcalcifications. •• On MRI, the primary mass is heterogeneously low T1 and high T2 signal with patchy heterogeneous postcontrast enhancement showing characteristic cerebriform pattern. Sometimes, obstructed secretions exhibit high T2 signal and do not enhance.

� Pearls & � Pitfalls ÛÛ A focal mass centered in the middle meatus causing

extensive bony remodeling without destruction and unilateral ostiomeatal unit obstructive type of opacification of frontal, ethmoidal, maxillary, and sphenoidal sinuses. ÚÚ Necrotic changes with high T2 signal may signify malignant change. Due to high recurrence rate and possibility of malignant transformation, postsurgical radiological follow-up is necessary.

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Case 25

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■■ Clinical Presentation A 12-year-old boy presents with a slightly progressive facial deformity.

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■■ Imaging Findings

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(A–D) Axial contrast-enhanced CT of the maxillofacial bones was obtained in bone algorithm (A, B), with coronal reformats in soft tissue and bone algorithms (C, D). Multiple expansile cystic areas of the mandible and maxilla are noted in a bilateral symmetrical distribution (arrows).

■■ Differential Diagnosis •• Cherubism: In a child or adolescent, this is the most likely diagnosis given the multifocal, symmetric bilateral nature of the lesions. •• Multiple odontogenic keratocysts (Gorlin syndrome): Could have a similar appearance but would expect other signs and symptoms (basal cell carcinomas, medulloblastomas, falx calcifications, etc.) and rather symmetric involvement would be unusual. •• Brown tumors of hyperparathyroidism: Could appear similar to the other two entities but would likely be more widespread in distribution involving other skeletal structures.

•• Clinically, patients will present with slowly progressive facial deformities as well as dental impaction and vision problems (due to maxillary involvement). •• Treatment is usually conservative due to the tendency for these lesions to regress. Surgical resection is reserved for severe or progressive disease.

■■ Other Imaging Findings •• MRI may demonstrate T1/T2 relative isointensity to muscle within the affected regions.

� Pearls & � Pitfalls

■■ Essential Facts

ÛÛ With this imaging appearance and a proper family his-

•• Cherubism is an autosomal dominant disease process similar to fibrous dysplasia resulting in expansile lesions within the mandible and maxilla with varying degrees of matrix. •• Cases typically develop during childhood or early adolescence with regression by early adulthood. However, some lesions may be more aggressive.

ÚÚ Early studies suggested that all cases of cherubism

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tory, the diagnosis is strongly suggested.

spared the mandibular condyles. However, condylar involvement has since been noted.

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Case 26

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■■ Clinical Presentation A 55-year-old woman presents with history of otitis media and recent onset sensorineural hearing loss.

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■■ Imaging Findings

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■■ Differential Diagnosis •• Cholesterol granuloma petrous apex: Expansile petrous apex lesion with thinning of cortical margins and trabecular erosion; high T1 and T2 signal mass marginated with a low T2 signal wall and without significant postcontrast enhancement. •• Petrous apex cholesteatoma: Smooth and expansile lesion on CT; low to intermediate T1 signal with intermediate to high T2 signal and rim enhancement on postcontrast MRI. •• Trapped fluid of petrous apex: Expansile petrous apex lesion with opacified air cells and intact cortical and trabecular margins. On MRI, it exhibits low to intermediate T1 signal and high T2 signal without evidence for significant postcontrast enhancement or meningeal enhancement. •• Petrus apicitis: Expansile lesion of petrous apex with permeative destructive changes of trabeculae; on MRI, low T1 and high T2 signal with peripheral rim enhancement and meningeal enhancement.

E

(A, B) Contrast-enhanced CT scan exhibits an expansile right petrous apex lesion with thinning and erosion of surrounding cortex (arrow) but without significant enhancement of the matrix of the lesion. Please note the dehiscence of the medial wall of the right carotid canal. (C–E) The rounded right petrous apex lesion exhibits high T1 signal and T2 signal with low T2 signal margins (arrow) and no significant postcontrast enhancement (arrow). See the extension of the lesion laterally into the dehiscent right carotid canal.

•• Most common presenting symptom is sensorineural hearing loss. Hemifacial spasm, facial numbness, tinnitus, and trigeminal neuralgia may also be seen. •• Surgical drainage or complete surgical resection are the most common treatment choices.

■■ Other Imaging Findings •• On CT, smooth, expansile, nonenhancing, petrous apex lesion with erosion of trabeculae and thinning of cortical margins is seen. •• On MRI, low T2 signal smooth wall of thinned out cortex or overlying dura is almost always seen. Characteristically, the lesion exhibits high T1 and high T2 signal secondary to presence of cholesterol crystals and breakdown products of blood. No significant postcontrast enhancement is seen.

� Pearls & � Pitfalls ÛÛ A smoothly expansile petrous apex mass on CT with

■■ Essential Facts •• It is a common petrous apex lesion in young to middleaged adults. •• Occurs secondary to chronic otitis media in a pneumatized petrous apex secondary to recurrent hemorrhages.

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trabecular breakdown and high T1 and T2 signal without significant postcontrast enhancement on MRI are characteristic. ÚÚ The expansile nature of petrous apex cholesterol granuloma should be differentiated from expansile and destructive petrous apex lesions secondary to infection and malignancy.

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Case 27

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■■ Clinical Presentation A 43-year-old man presents with intermittent neck pain.

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■■ Imaging Findings

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(A–C) Axial contrast-enhanced CT images were obtained of the neck and were reviewed in soft tissue (A, B) and bone windows (C). There is a calcified focus along the expected location of Wharton’s duct (circles) with proximal ductal enlargement (arrow). There is mild enlargement of the left submandibular gland (asterisk).

■■ Differential Diagnosis •• Wharton’s duct calculus with obstructive sialadenitis: This is by far the most likely diagnosis given the combination of a calculus with associated glandular enlargement. •• Squamous cell carcinoma of the distal Wharton’s duct: Would not calcify but could occlude the duct distally resulting in proximal dilatation with extension to the submandibular gland. •• Nonobstructive sialadenitis: The gland could appear similarly in the absence of an obstructing lesion. However, no ductal enlargement would be present.

•• Treatment is surgical, often only requiring an intraoral incision for calculi located within the distal duct. More proximal calculi may require resection of the gland as well.

■■ Other Imaging Findings •• Although the majority of obstructing calculi are visible on plain radiographs, such films are not typically acquired.

� Pearls & � Pitfalls ■■ Essential Facts •• Sialadenitis can be divided into obstructive and nonobstructive causes. Calculi are the most common cause of obstructive sialadenitis. •• The submandibular gland is the salivary gland more often affected by calculi (in comparison to the parotid gland) due to horizontal, upward flow and content of its secretions. •• Pain is the most common complaint, usually colicky in nature, particularly at meal times due to increased secretion production. •• CT is the method of choice for diagnosis due to the ability to visualize the calculus as well as any adjacent inflammatory change within the submandibular gland.

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ÛÛ Sialoliths are much more commonly seen in or along

the submandibular glands in comparison to the parotid glands. ÚÚ Obstructing oral cavity carcinomas can also result in ductal enlargement. Thus, correlation of radiographic findings with intraoral inspection is required. ÚÚ Occasionally, small calculi will be difficult to differentiate from vessels. Noncontrast CT images may be of value.

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Case 28

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■■ Clinical Presentation A 24-year-old man presents with history of recent cold and sudden onset facial nerve palsy.

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■■ Imaging Findings

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■■ Differential Diagnosis •• Bell palsy: Linear enhancement of the labyrinthine segment, geniculate ganglion, or proximal tympanic intratemporal facial nerve on T1 postgadolinium contrast imaging in a patient with sudden onset unilateral weakness of facial muscles with history of recent viral infection. •• Normal enhancement of facial nerve: Perineural venous plexus gives rise to patchy discontiguous enhancement, seen more commonly at posterior genu and mastoid segments. Premeatal and labyrinthine segments are commonly uninvolved. •• Hemangioma of facial nerve: Irregular and ill-defined mass is seen involving the anterior geniculate ganglion. CT shows widening of geniculate fossa and permeative bone changes with intratumoral bone spicules. •• Perineural spread of skull base mass: Ascending perineural spread along the mastoid segment with widening of the mastoid portion of the facial nerve canal. History of parotid mass is common.

B

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(A–D) Patchy linear enhancement in labyrinthine segment (arrow) extending in to the geniculate fossa and proximal intratemporal tympanic segment (arrow) and mastoid segment (arrow) of the facial nerve.

•• Medical treatment with steroids and acyclovir is the preferred treatment. Spontaneous recovery without therapy is possible in the first 2 months. Severe facial nerve palsy due to denervation may be treated with surgical decompression.

■■ Other Imaging Findings •• Temporal bone CT may show normal facial nerve canal. •• On MRI, uniform linear enhancement without nodularity or increase in size of facial nerve on ipsilateral side may be seen. The enhancement is generally seen at the intratemporal labyrinthine segment, geniculate ganglion, or proximal tympanic segment. It is possible to have enhancement of the internal auditory canal (IAC) fundal segment.

� Pearls & � Pitfalls ÛÛ Classic clinical presentation of acute onset Bell palsy

■■ Essential Facts •• Acute onset palsy of the facial nerve may be preceded by a viral infection. A herpetic etiology is suspected in more than half of the cases. •• Facial pain and numbness with alteration in taste are frequently associated findings.

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may result in spontaneous recovery in first 2 months. In that case, the imaging is required. MRI is generally performed for atypical cases. ÚÚ Temporal bone CT is unhelpful.

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Case 29

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■■ Clinical Presentation A 40-year-old man presents with pulsatile tinnitus.

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■■ Imaging Findings

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■■ Differential Diagnosis •• Glomus tympanicum (GT): In the setting of pulsatile tinnitus, this is the most likely diagnosis given a mass along the cochlear promontory. Otoscopic exam should demonstrate a red, vascular mass. •• Aberrant internal carotid artery (ICA): May present as a vascular mass along the middle ear, resulting in tinnitus. However, the carotid canal is not dehiscent on this exam. •• Cholesteatoma: This could present as a soft tissue mass in the middle ear. However, these lesions are typically located in Prussak’s space, along the epitympanum, and do not result in pulsatile tinnitus.

■■ Essential Facts •• Glomus tympanicum is a paraganglioma, a type of tumor that arises from chemoreceptor cells of the sympathetic nervous system. •• Glomus tympanicum tumors usually present with pulsatile tinnitus or conductive hearing loss. Otoscopic exam reveals a red, vascular mass. •• Temporal bone CT usually demonstrates a soft tissue mass usually along the cochlear promontory within the middle ear. However, GTs can occur anywhere along the expected location of Jacobson’s nerve.

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D

(A–D) High-resolution noncontrast axial CT images were obtained through the right temporal bone (A, B) with coronal reformats (C, D). There is a small soft tissue mass situated along the cochlear promontory (arrows). Note that the right carotid canal is intact (arrowhead).

•• Glomus tumors of the head and neck primarily occur within the middle ear (glomus tympanicum) as well as along the jugular foramen (glomus jugulare) and along the carotid bifurcation (carotid body tumor). •• These tumors are typically chemically silent and come to attention due to effects caused by the tumor locally. •• The typical patient for a glomus tumor is a middle-aged woman; however, they can occur at any age.

■■ Other Imaging Findings •• Temporal bone CT is excellent at demonstrating a suspected GT and is the first-line imaging choice. •• MRI can be helpful for larger lesions. Such lesions often demonstrate a “salt and pepper” appearance on imaging due to flow voids and prior areas of hemorrhage.

� Pearls & � Pitfalls ÛÛ Correlation with otoscopic exam should suggest the diagnosis of GT.

ÚÚ However, one must always exclude an aberrant ICA or other vascular anomaly as the cause of the physical findings.

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Case 30

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■■ Clinical Presentation 23-year-old female with progressive mixed conductive and sensorineural hearing loss.

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■■ Imaging Findings

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■■ Differential Diagnosis •• Cochlear otosclerosis: Rim of lucency surrounding the cochlea within the otic capsule, generally bilateral in a patient with gradual progressive mixed conductive and sensorineural hearing loss. Simultaneous presence of fenestral otosclerosis may also be seen. •• Osteogenesis imperfect: Children with brittle bone disease can have this change of the otic capsule. The appearance is radiologically indistinguishable from the severe form of cochlear otosclerosis; however, bone involvement is generalized. •• Paget disease: Usually not confined to pericochlear region with diffuse involvement of bony labyrinth; seen in elderly population. •• Fibrous dysplasia: Sclerotic and ground-glass appearance of the whole temporal bone with relative sparing of the otic capsule region.

■■ Essential Facts •• In general, it is seen in conjunction with fenestral otosclerosis and is considered a late manifestation of the same process. •• There is spongiotic remodeling of the otic capsule resulting in resorption of normal bone with irregular new bone formation in late stage. •• More common in 2nd and 3rd decade of life with female predominance.

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B

D

(A–D) Curvilinear lucencies within the otic capsule in the pericochlear bony labyrinth (white arrows). There is also lucency at the region of the fissula ante fenestral (black arrow), compatible with fenestral otosclerosis.

•• Progressive mixed conductive hearing loss followed by sensorineural hearing loss is a common presentation. Tinnitus may also be present. •• Treatment with fluoride can help arrest the progression.

■■ Other Imaging Findings •• On temporal bone CT, there is presence of low density within the bony labyrinth with a halo-like appearance in the pericochlear otic capsule. In chronic stage, there is a ring of low density surrounding the cochlea with a double ring sign. In the late stage, a band of thick sclerotic rim surrounds the cochlea within the otic capsule. •• Simultaneous lucency around the oval and round windows may be seen, compatible with fenestral otosclerosis. •• On MRI, pericochlear linear faint enhancement may be seen corresponding to lucencies on CT scan, seen on fat-suppressed postcontrast T1-weighted images.

� Pearls & � Pitfalls ÛÛ Progressive gradual mixed conductive and sensorineu-

ral hearing loss with presence of lucencies in pericochlear region within the otic capsule, which is more often seen bilaterally. ÚÚ It is not as common as fenestral otosclerosis; however, if not treated, it can lead to total deafness.

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Case 31

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■■ Clinical Presentation A 12-year-old boy presents with developmental delay.

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■■ Imaging Findings

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(A, B) Sagittal T1-weighted images were obtained through the sella turcica before (A) and after contrast administration (B). (C, D) Additional coronal T1 pre- (C) and postcontrast (D) images were obtained. There is a focus of T1 shortening along the posterior aspect of the sella (arrows). No abnormal contrast enhancement is noted.

■■ Differential Diagnosis •• Rathke’s cleft cyst (RCC): This would be one of two top imaging differential diagnoses depending on the clinical scenario. An incidentally found lesion such as this within the sella turcica would likely be this entity. •• Craniopharyngioma: Less likely possibility due to lack of abnormal contrast enhancement; may be difficult to differentiate from RCC if small. •• Pituitary apoplexy: In a younger patient with abrupt onset of headaches and visual symptoms, a hemorrhagic adenoma could have a similar appearance. One would expect to see some enhancement, but this may not necessarily be present.

■■ Essential Facts •• RCC is a remnant of Rathke’s pouch, an embryological intracranial structure that normally regresses before birth. •• Residual cleft results in gradual cyst formation in the sellar/suprasellar regions, usually incidentally noted on an exam ordered for other reasons. •• Patients may be asymptomatic or present with signs and symptoms related to local mass effect against the sellar contents on the optic chiasm. •• Cysts can have a variety of T1/T2 signal characteristics based on the fluid contents. There may be thin peripheral enhancement of the wall.

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•• Transsphenoidal drainage is the treatment of choice, although smaller lesions may just be observed.

■■ Other Imaging Findings •• CT scan may demonstrate cystic enlargement of the sella, which may be confused for an empty sella turcica. •• Calcification along a sellar lesion may suggest another diagnosis such as a craniopharyngioma.

� Pearls & � Pitfalls ÛÛ Common lesion, often incidentally found. ÚÚ Other lesions can appear similarly. Remember the

SATCHMO differential diagnosis for other entities in this area. � Sarcoidosis � Aneurysm � Teratoma � Craniopharyngioma � Hamartoma or glioma of the hypothalamus, histiocytosis � Meningioma, metastasis � Optic nerve glioma

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Case 32

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■■ Clinical Presentation A 26-year-old man presents with history of neurofibromatosis type 2 (NF2) and gradual sensorineural hearing loss and vertigo.

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■■ Imaging Findings

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(A) T2-weighted axial imaging exhibits low T2 signal filling defect (arrow) within the vestibule, extending into the lateral semicircular canal with presence of similarly low T2 signal mass filling up and expanding the right internal auditory canal (IAC). High T2 signal trapped fluid is seen at left petrous apex. (B) Postcontrast T1 axial imaging exhibits intense enhancement of right IAC mass and right intravestibular mass (arrow). (C) Postcontrast T1 coronal image exhibits intense postcontrast enhancement of vestibule and adjoining semicircular canals (arrow). (D) Volumetric 3D FIESTA imaging exhibits a low T2 signal filling defect (arrow) within high T2 signal vestibular fluid.

■■ Differential Diagnosis •• Intravestibular schwannoma with acoustic schwannoma within the IAC: Intensely enhancing low T2 signal intravestibular filling defect conforming to the contour of the membranous labyrinth without expansion. Larger mass with similar signal and contrast characteristics is also visualized within the right IAC. •• Schwannoma of facial nerve: Lobulated and tubular expansile mass within intratemporal facial nerve canal with secondary involvement of membranous labyrinth. •• Labyrinthitis: Linear enhancement of cochlea and vestibule on postcontrast imaging; however, no evidence of a filling defect within the membranous labyrinth on T2-weighted images.

•• Surgery performed only in cases of intractable disabling symptoms like vertigo that result in total deafness.

■■ Other Imaging Findings •• Intralabyrinthine schwannoma may have normal temporal bone CT scan. •• On MRI, low T2 signal mass is visualized within high T2 signal cochlea or vestibule as a filling defect. •• Volumetric T2-weighted 3D sequences like FIESTA delineate a low T2 signal mass, contrasted against high T2 signal fluid of cochlea and vestibule. •• On postcontrast T1-weighted imaging, intense focal enhancement of intralabyrinthine schwannoma is seen.

■■ Essential Facts

� Pearls & � Pitfalls

•• Slow-growing benign neoplasm originating from Schwann cells along the distal cochlear or vestibular nerve within the membranous labyrinth. •• It may be present in conjunction with IAC/cerebellopontine angle (CPA) masses or may stand alone. •• Intravestibular mass presents with tinnitus, vertigo, nausea, vomiting, and mixed hearing loss. Intracochlear mass presents with slowly progressive sensorineural hearing loss.

ÛÛ Normal temporal bone CT with low T2 signal filling

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defect within high T2 signal fluid of cochlea or vestibule on volumetric T2-weighted imaging like FIESTA in a patient with sensorineural hearing loss, tinnitus, vertigo, or Ménière disease. ÚÚ Subtly enhancing intralabyrinthine schwannoma is often missed on brain MRI.

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Case 33

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■■ Clinical Presentation A 7-year-old boy presents with an anterior neck mass.

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■■ Imaging Findings

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(A–C) Contrast-enhanced axial CT images were obtained through the neck (A, B) with sagittal reconstructions (C). There is a cystic lesion with minimal wall enhancement (arrows) noted along the right neck strap musculature.

■■ Differential Diagnosis •• Thyroglossal duct cyst (TDC): Incidental or symptomatic cystic lesion found at this location in a child or young adult is most likely a TGC. •• Branchial cleft cyst (BCC): An additional cystic neck lesion often found in the pediatric population. However, the above lesion is rather medial for a BCC. •• Venolymphatic malformation: Could have a very similar appearance, particularly if it is a predominantly lymphatic lesion.

■■ Essential Facts •• TDCs can be found anywhere from the foramen cecum (superiorly) to the thyroid gland (inferiorly), including along the hyoid bone and within the larynx. •• TDCs represent embryonic remnants from prior thyroid gland migration. Most remain asymptomatic until after an upper respiratory infection, when they can become tender and increase in size.

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•• A Sistrunk procedure is performed for removal of such lesions, which includes resection of a portion of the hyoid bone and tissue along the expected location of the duct. •• Recurrence is uncommon (, 5%) but requires greater surgical intervention for removal.

■■ Other Imaging Findings •• Ultrasound is also considered a first-line diagnostic tool, as it can accurately localize the cyst and suggest the diagnosis without radiation. •• Such lesions may also be seen on an MRI of the neck.

� Pearls & � Pitfalls ÛÛ Common congenital lesion of the neck. ÚÚ Carcinoma can be seen in a small minority (, 3%) of

patients, particularly if there is a nodular component. Thus, these lesions should be resected.

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Case 34

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■■ Clinical Presentation A 3-year-old presents with congenital sensorineural hearing loss.

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■■ Imaging Findings

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(A–B) There is complete aplasia of the cochlea. The vestibule appears to be dilated with dysmorphic semicircular canals. There is the presence of an unusual configuration of cochlea (arrow), where a normal-appearing basal turn of cochlea separated from the middle turn. (C) The vestibular aqueduct is dilated, whereas the second and apical turn of cochlea coalesce to form a single cavity (arrow).

■■ Differential Diagnosis

■■ Other Imaging Findings

•• Cochlear dysplasia: Lack of classic 2½ turns of normal cochlea on temporal bone CT with presence of a cystic cochlea, incomplete partition, or bulbous apical turn in a patient with congenital sensorineural hearing loss. •• Cystic vestibular dysplasia: Enlarged vestibule and lateral semicircular canal. If isolated vestibular anomaly, hearing may be normal. •• Cochlear aplasia: Most severe form of dysplasia with total lack of cochlear cavity or vestibule.

•• In mild dysplasia, the apical turn is mildly dilated. Moderate dysplasia, also known as incomplete partition, shows a well-defined basal turn but fused middle and apical turns. In severe dysplasia, a single cystic cochlear cavity without individual turns is seen. This is often associated with a cystic vestibule. •• Similar configuration is seen on T2-weighted MRI, which however is more sensitive to detect possible aplasia of cochlear nerve. The anterior scala vestibuli appears to be larger than the posterior scala tympani. •• One-mm high-resolution temporal bone CT and/or volumetric 3D FIESTA imaging is recommended for more accurate diagnosis.

■■ Essential Facts •• Lack of development of normal 2½ turns of cochlea. Previously called Mondini malformation, it is a spectrum of mild to severe dysplasia. •• Mild dysplasia results in incomplete development of the apical turn of cochlea with modiolar deficiency. •• Moderate dysplasia results in incomplete development of apical and middle turns of cochlea, and modiolar deficiency. •• Severe dysplasia results in single cystic cavity without an internal architecture of cochlea. Modiolar deficiency with a hypoplastic cochlear nerve is seen. •• Most common presentation, often bilateral, is congenital sensorineural hearing loss. •• Profound bilateral sensorineural hearing loss can be treated with cochlear implantation.

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� Pearls & � Pitfalls ÛÛ Lack of normal 2½ turns of the cochlea on temporal

bone CT with varying spectrum of dysplastic appearance is diagnostic. ÛÛ It is usually associated with large vestibular aqueduct anomaly. ÚÚ Sometimes mild cochlear dysplasia with a mildly bulbous apical turn and modiolar deficiency is difficult to diagnose on CT scan.

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Case 35

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■■ Clinical Presentation A 15-year-old boy presents with progressive sensorineural hearing loss.

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■■ Imaging Findings

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(A–D) High-resolution noncontrast axial (A, B) and coronal (C, D) images were obtained through the temporal bones. There is diffuse, smooth enlargement of the left vestibular aqueduct (arrowheads).

■■ Differential Diagnosis •• Enlarged vestibular aqueduct (congenital): In a young patient with progressive hearing loss and smooth enlargement of the aqueduct, this is the most likely diagnosis. •• Endolymphatic sac tumor: Usually seen in a slightly older population, particularly in patients with von Hippel– Lindau disease. Bone margins are erosive rather than smooth. •• Other cerebellopontine angle lesions (meningiomas, epidermoid, etc.): Such lesions are typically not centered within the vestibular aqueduct.

trauma (even minor) does appear to cause progression of symptoms. •• Enlargement is best seen on temporal bone CT where the normal aqueduct should measure , 1.5 mm or the size of the adjacent posterior semicircular canal. •• Can be isolated but is often seen with malformations of the cochlea.

■■ Other Imaging Findings •• CT is the diagnostic method of choice. However, highresolution MRI may also demonstrate such findings.

■■ Essential Facts

� Pearls & � Pitfalls

•• Congenital enlargement of the vestibular aqueduct and endolymphatic sac is the most commonly seen cause of sensorineural hearing loss. •• Patients present with progressive sensorineural hearing loss, the mechanism of which is unclear. However,

ÛÛ Relatively common cause of sensorineural hearing loss

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in children. Thoroughly evaluate the aqueduct on such patient scans. ÚÚ Cochlear malformations may also be present and must be evaluated at the time of CT.

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Case 36

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■■ Clinical Presentation A 28-year-old woman presents with lazy eye syndrome and swelling of the face.

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■■ Imaging Findings

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(A, B) Axial and coronal sinus CT exhibits a well-defined, expansile mass of the right maxillary sinus (arrow), extending laterally into the infratemporal fossa, posteriorly into the pterygopalatine fossa (arrowhead), medially into the nasal passage (arrow), inferiorly eroding the maxillary ridge (arrowhead), and superiorly into the inferior part of the right orbital cavity with resultant exophthalmos. A thick irregular rim surrounds a central low attenuating stroma. (C–F) A low T1 signal expansile mass exhibits heterogeneous T2 signal (arrow). The area of bony rim has very low T2 signal (arrow). Intense but heterogeneous postcontrast enhancement of the expansile mass is seen. See the posterior extension into pterygopalatine fossa (arrowhead) and inferior erosion of maxillary ridge (arrowhead).

■■ Differential Diagnosis •• Ossifying fibroma: Well-defined, monostotic expansile soft tissue mass of paranasal sinuses is seen with a rim of mature bone surrounding uni- or multilocular low attenuating center of fibrous tissue. It is more commonly seen at the ethmoidal, sphenoidal, or maxillary sinuses. •• Sinonasal osteoma: It is a lesion of flat lamellar bone, commonly seen in frontal sinus. •• Fibrous dysplasia: Poorly defined expansile mass is seen with ground-glass appearance, more commonly seen in maxillary sinus. It may be polyostotic.

■■ Essential Facts •• A benign mixed soft tissue and ossific sinus mass that is slow-growing and may be locally aggressive. It is composed of fibrous tissue and mature bone. •• It is generally asymptomatic and may be discovered incidentally. Symptoms pertain to nasal obstruction with pain, facial swelling, chronic sinusitis, and, later, mucocele formation.

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•• Generally affects the young adult with female preponderance. •• Surgical resection is treatment of choice.

■■ Other Imaging Findings •• On CT, a well-marginated, expansile, ossific mass of paranasal sinuses is seen with thick bony rim and a low attenuation soft tissue fibrous center. Ethmoidal and sphenoidal sinuses are more commonly affected than maxillary. •• On MRI, a low T1 and heterogeneously high to low T2 signal mass is seen with postgadolinium contrast enhancement of the stroma.

� Pearls & � Pitfalls ÛÛ A well-defined, expansile, benign mass of paranasal si-

nuses with an osseous thick peripheral rim surrounding a central low-density soft tissue in a young woman. ÚÚ There is high recurrence rate, even after total surgical resection.

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Case 37

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■■ Clinical Presentation A 5-year-old boy presents with a neck lump.

■■ Further Work-up An additional test was performed.

C

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■■ Imaging Findings

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(A, B) Axial contrast-enhanced CT of the neck was obtained. There is a cystic lesion centered within the right neck (black arrows). (C, D) An axial T2-weighted MRI (C) with fat saturation as well as a contrast-enhanced T1-weighted axial MRI (D) were then obtained. The lesion is transpatial, extending from the retropharyngeal space (white arrows) to the right carotid space (arrowheads).

■■ Differential Diagnosis •• Venolymphatic malformation (VLM): This is at the top of the differential list due to the patient’s age and radiographic findings of a transpatial soft tissue lesion with multiple septations and lack of significant solid enhancement. •• Branchial cleft cyst: Could also be considered in the differential of cystic lesions of the neck extending across multiple spaces. However, such lesions are most commonly tubular. •• Necrotic lymph node: A conglomerate of necrotic lymph nodes could appear similarly. One might expect other abnormal nodes at other locations given the size of this lesion.

■■ Essential Facts •• Venolymphatic malformations are a group of slow flow congenital malformations consisting of various amounts of venous and lymphatic tissue. If primarily lymphatic, it is often referred to as cystic hygromas. •• Lesions may go unnoticed clinically for a long time—if small, until trauma or infection causes some degree of edema/enlargement. •• Lesions can have several MR appearances based on the amount of venous or lymphatic tissue present. Venous portions demonstrate contrast enhancement.

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•• Lymphatic, cystic areas demonstrate extensive T2 prolongation with peripheral enhancement. Fluid–fluid levels can be seen in such lesions. •• Therapy can include a combination of sclerotherapy and/ or surgical intervention.

■■ Other Imaging Findings •• Lesions can be transpatial (in comparison to many other lesions of the head and neck), which can further suggest the diagnosis.

� Pearls & � Pitfalls ÛÛ VLMs can be transpatial, suggesting the diagnosis. ÛÛ The presence of round calcifications (phleboliths) on CT further suggests the diagnosis.

ÚÚ Although benign, such lesions can grow and should be referred to appropriate specialty care.

ÚÚ Rarely, other more aggressive lesions can have a similar appearance.

ÚÚ Mapping out the full extent of the lesion is necessary if surgical resection is to be performed.

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Case 38

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■■ Clinical Presentation A 60-year-old man presents with chronic sinusitis, nasal obstruction, facial pressure, and pain. He also complains of photophobia and ocular pressure.

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■■ Imaging Findings

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(A–C) On sinus CT, an irregular sinonasal mass, centered in the nasal cavity and ethmoidal sinuses, also exhibits perforation of the nasal septum and destruction of the medial walls of the maxillary sinuses including the uncinate process. (D, E) On sinus MRI, extensive bone destruction of the nasal septum and medial maxillary walls is seen. The ethmoidal sinus mass is predominantly hypointense on T2-weighted images and enhances intensely on postcontrast imaging (arrows). Pockets of high T2 signal exhibit only postcontrast enhancement and likely represent retained obstructed mucus collection. There is leptomeningeal enhancement at the floor of the anterior cranial fossa extending into the orbit likely due to direct invasion. (F, G) One-year follow-up CT scan of the sinus reveals irregular thickening of the sinus walls compatible with a chronic inflammatory process with persistent maxillary sinus opacification.

■■ Differential Diagnosis •• Wegener granulomatosis: Sinonasal low T2 signal soft tissue mass with septal and nonseptal bone destruction in an elderly male presenting with chronic sinusitis. The mass exhibits low T2 signal on MRI—incidental high T2 signal is seen in sinusitis. Meningeal enhancement or orbital involvement in a small number of cases is seen as a late manifestation. •• Cocaine abuse: Septal perforation is a common finding with inflammatory changes at the sinonasal cavity. Involvement of other organs is not seen. Obtaining relevant history helps the diagnosis. •• Non-Hodgkin lymphoma: Sinonasal soft tissue mass with septal and nonseptal bone destruction. The mass also reveals low T2 signal and invasive characteristics for the orbit and intracranial compartment. However, there is a lack of tracheobronchial and renal involvement. •• Sarcoidosis: Sinonasal mass with septal and known septal bone destruction. Also reveals low T2 signal. However, it is more commonly seen in African-Americans. Renal involvement is rare.

■■ Essential Facts •• It is an idiopathic, multinucleated, giant cell granuloma of unknown etiology involving the nose, lungs, and kidneys. Also known as midline nonhealing granuloma. •• Most common presentation is nasal obstruction and epistaxis. Other symptoms include anosmia, rhinorrhea,

Case_038_075-076.indd 76

and sinonasal pain. It is commonly mistaken as chronic sinusitis. •• It is a disease of the middle-aged to elderly population with male predominance. •• The classic clinical triad includes respiratory tract necrotizing granuloma, necrotizing vasculitis, and glomerulonephritis. •• Treatment includes steroids and oral cyclophosphamide. Surgery may be performed for late manifestations like “saddle nose” deformity.

■■ Other Imaging Findings •• On CT scan, an irregular soft tissue mass is seen with associated nasal septum perforation and bone destruction. Erosive changes can be seen at the medial wall of the maxillary sinus, uncinate process, and nasal turbinates. •• On MRI, the sinonasal granulomatous mass exhibits low T2 signal with intense postcontrast enhancement. •• Meningeal enhancement and orbital involvement are generally seen as late findings.

� Pearls & � Pitfalls ÛÛ The sinonasal soft tissue mass with septal and known sep-

tal bone destruction in the middle-aged to elderly population is highly suspicious for Wegener granulomatosis. ÚÚ Based only on imaging findings, it is not possible to differentiate from sarcoidosis or lymphoma. Look for involvement or lack thereof from the tracheobronchial tree and kidneys.

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Case 39

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■■ Clinical Presentation A 27-year-old man presents with dizziness.

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■■ Imaging Findings

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D

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(A, B) Multiple axial MRI images were obtained through the cerebellopontine angles (CPA). There is subtle expansion of the left CPA (arrowheads) on the axial T1 postcontrast and T2-weighted images. (C) CISS imaging suggests that there truly is a lesion in this area (arrowhead). (D) This region of expansion within the left CPA is further characterized by high signal on the diffusion-weighted images (arrow).

■■ Differential Diagnosis •• Epidermoid cyst: A left CPA lesion with restricted diffusion clinches the diagnosis, as other entities, such as arachnoid cysts, should not restrict diffusion. •• Arachnoid cyst: Conventional MRI signal changes mimic those for an epidermoid and are generally noted to parallel CSF signal. However, arachnoid cysts will not restrict diffusion. •• Cystic meningioma: Typically will demonstrate some portion that solidly enhances.

■■ Essential Facts •• Epidermoid cysts are congenital lesions due to ectodermal inclusions during embryonic life. Over time, these cysts fill with material from the wall. •• Patients typically present during the third and fourth decades of life with dizziness, hearing loss, or facial nerve palsy. Patients may also be asymptomatic. •• Epidermoids will parallel CSF signal intensity on conventional MR sequences. However, there is typically some signal change noted on heavily T2-weighted and FLAIR imaging.

Case_039_077-078.indd 78

•• The hallmark finding of an epidermoid cyst is restricted diffusion on diffusion-weighted sequences. •• These lesions are typically surgically removed. •• Epidermoids are common CPA tumors, along with other entities such as meningiomas, arachnoid cysts, and aneurysms.

■■ Other Imaging Findings •• Bony remodeling may be seen on CT, as these are slowgrowing lesions.

� Pearls & � Pitfalls ÛÛ Restricted diffusion differentiates these lesions from others.

ÚÚ If small (as in our case), epidermoids can be difficult to see without diffusion-weighted imaging.

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Case 40

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■■ Clinical Presentation A 36-year-old presents with right-sided progressive conductive hearing loss and a history of chronic otitis media.

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■■ Imaging Findings

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B

C

D

(A–C) An irregular soft tissue mass (arrow) at posterior mesotympanum, medial to the ossicular chain, causes extensive erosion of the long process of incus (arrow) and superstructure of stapes. The mass involves the sinus tympani and facial nerve recess and extends up to the foramen ovale. There is bony erosion of the tegmen tympani. (D) Restricted diffusion (arrow) is seen on diffusion-weighted MRI.

■■ Differential Diagnosis

■■ Other Imaging Findings

•• Pars tensa cholesteatoma: Nonenhancing soft tissue at posterior mesotympanum, involving the sinus tympani and facial nerve recess and situated medial to the ossicular chain. There is erosion of the long process of incus as well as superstructure of stapes. •• Chronic otitis media with granulation: Erosion of ossicular chain is less common. It may exhibit contrast enhancement, especially on MRI. •• Cholesterol granuloma of middle ear: May exhibit ossicular erosion on CT. On MRI, a high T1 signal nonenhancing mass without impeded diffusion is seen.

•• On CT scan, a nonenhancing soft tissue mass is seen at posterior mesotympanum involving the sinus tympani and facial nerve recess and situated medial to the ossicular chain. Erosion of the ossicular chain is a common finding and is generally seen in the following order: the long process of incus, stapes superstructure, and manubrium of the malleus. When large, it is contiguous with opacified mastoid air cells through the aditus ad antrum. •• On MRI, a nonenhancing low T1 and mildly high T2 signal middle ear mass with impeded diffusion is seen. Intracranial complications are best visualized with MRI. •• Presence of labyrinthine fistulae, erosion of the tegmen tympani, and the dehiscence of the facial nerve canal are other common complications that can be evaluated better on CT.

■■ Essential Facts •• It is a secondary acquired cholesteatoma secondary to focal accumulation of keratin material seen with relation to pars tensa of tympanic membrane and situated in posterior mesotympanum. •• History of previous chronic otitis media, tympanic membrane perforation, temporal bone fracture, or previous middle ear surgery is common. •• Most common clinical presentation is unilateral progressive conductive hearing loss. Other symptoms include otalgia, headaches, and otorrhea. Vertigo, sensorineural hearing loss, or facial nerve palsy may represent secondary complications. •• Commonly seen in pediatric and adult age groups. •• Surgical removal of cholesteatoma with different type of mastoidectomies is the preferred treatment. Reconstruction of auditory ossicles and tympanic membrane may be necessary per extent of the disease.

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� Pearls & � Pitfalls ÛÛ Axial and coronal CT scan of temporal bone defines

the location and extent; detects ossicular erosion; and evaluates possible complications like labyrinthine fistulae, erosion of the tegmen tympani, and the dehiscence of the facial nerve canal. ÚÚ MRI better evaluates intracranial complications and is needed to differentiate from conditions like chronic granulation and cholesterol granuloma.

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Case 41

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A

■■ Clinical Presentation An 8-year-old boy presents with nasal obstruction.

■■ Further Work-up An additional test was ordered.

C

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■■ Imaging Findings

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C

■■ Differential Diagnosis •• Sinonasal polyp: Given the fluid attenuation and extensive T2 prolongation, this should rank high on the list. The lesions lack destructive or aggressive features. Some internal enhancement (angiomatous) elements can be present. •• Juvenile nasopharyngeal angiofibroma (JNA): As these are almost always found in adolescent men, the age range is not quite right but the gender is. Such lesions, however, also tend to expand the sphenopalatine foramen and pterygopalatine fossa. •• Inverted papilloma: Can appear similar to more angiomatous polyps on imaging. However, the age range is not congruent with our patient (40–70 years old). Also, these lesions tend to enhance in a more solid fashion and are less T2 hyperintense. These lesions are associated with increased incidence of nasal squamous cell carcinomas.

■■ Essential Facts •• Polyps are common intranasal mass lesions, resulting from trapped fluid in the deeper layers of the mucosa of the nasal cavity. These can occur in any age group and can extend into the adjacent paranasal sinuses as well as posteriorly into the pharynx.

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B

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Axial (A) and sagittal (B) reconstructed contrastenhanced CT images of the maxillofacial bones were acquired. There is an extensive fluid-attenuated lesion filling the right maxillary sinus (black arrows), nasal cavity, and nasopharynx (black arrows), without disruption of adjacent structures. Sagittal T2-weighted (C) and contrast-enhanced axial T1-weighted fat-suppressed (D) images demonstrate a predominantly peripherally enhancing focus (white arrows) with extensive T2 prolongation (white arrow).

•• Key imaging findings include peripheral enhancement with relative lack of internal enhancement. Lesions are extensively T2 hyperintense on MRI and tend to remodel rather than destroy adjacent structures. •• Any intranasal lesion, however, should be correlated with direct visual inspection and clinical history.

■■ Other Imaging Findings •• On CT, polyps are of low (fluid) attenuation. However, polyps with more inspissated secretions can be of higher density. Such polyps may be difficult to differentiate from other lesions by CT alone.

� Pearls & � Pitfalls ÛÛ Nasal lesions, which are very bright on T2-weighted

images, are quite likely to be inflammatory in nature rather than neoplastic. ÛÛ JNAs tend to involve the sphenopalatine fossa. ÚÚ Extensive conglomerate polyps can be difficult to differentiate from a mass lesion. Intact bony structures (septae, nasal turbinates, and sinus walls) and high CT attenuation of the lesion would suggest a benign process.

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Case 42

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■■ Clinical Presentation Paranasal sinus osteoma.

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■■ Imaging Findings

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(A, B) Coronal CT with soft tissue and bone window exhibit an anterior ethmoidal sinus bony mass projecting off the anterior inferior frontal sinus. The mass also involves the right lamina papyracea. (C, D) Axial CT with soft tissue and bone window exhibit an expansile bony mass at anterior ethmoidal air cells expanding into right orbital cavity.

■■ Differential Diagnosis

■■ Other Imaging Findings

•• Paranasal sinus osteoma: Well-marginated, expansile mass in the frontal ethmoidal sinus involving the sinus walls with dense bony matrix. •• Ossifying fibroma: Well-marginated, expansile mass of the paranasal sinus with a rim of mature bone surrounding fibro-osseous low-density matrix. •• Fibrous dysplasia: Poorly defined, expansile mass with ground-glass matrix is seen. •• Osteosarcoma: Irregular, invasive mass with osteoid matrix; permeative margins and a periosteal elevation are seen.

•• On CT scan, a well-defined, expansile, and sessile mass with osteoid matrix arising from the wall of a paranasal sinus and protruding into its lumen is seen. •• On MRI, it displays low T2 signal cortical rim with variable signal of the matrix. A highly ossified mass can have low T1 and T2 signal and may be confused with air. •• Sinus secretions or mucocele formation can be seen due to obstruction of drainage. Rare cases with larger masses may be associated with pneumocephalus or brain abscess.

■■ Essential Facts •• Sinonasal osteoma is the most common benign neoplasm of paranasal sinuses. •• It is mostly asymptomatic and discovered as an incidental finding. When present, the symptoms relate to obstruction of sinus drainage. Headaches, chronic sinusitis, and facial pain are common symptoms. •• It is more commonly discovered in the elderly population with female preponderance. •• It predominantly arises in the frontal and ethmoidal sinuses rather than maxillary and sphenoidal. Multiplicity of osteomas is associated with Gardner syndrome.

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� Pearls & � Pitfalls ÛÛ Thin section noncontrast CT with coronal reconstruc-

tion and bone window is the investigation of choice for diagnosis. ÚÚ Sometimes it is difficult to differentiate from ossifying fibroma.

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Case 43

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■■ Clinical Presentation A 28-year-old woman presents with visual changes.

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■■ Imaging Findings

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(A–C) Coronal T2 fat-saturated (A), axial T1 precontrast (B), and axial T1 postcontrast fat-saturated images (C) demonstrate a mass lesion within the intraconal aspect of the right orbit (arrows). The lesion is T2 hyperintense, demonstrates contrast enhancement, and is rather well circumscribed.

■■ Differential Diagnosis •• Orbital hemangioma: In an adult, a well-circumscribed intraconal lesion could very well represent a hemangioma, especially in an otherwise healthy patient. •• Orbital schwannoma: Could also have a similar appearance but is much less commonly encountered. •• Orbital meningioma: Again, less commonly encountered and is usually found along the course of the optic nerve.

■■ Essential Facts •• Orbital hemangiomas are tumors composed of dilated vascular channels. Unlike pediatric capillary hemangiomas, adult cavernous hemangiomas will not involute but will instead grow over time. •• Orbital hemangiomas represent the most common primary adult orbital tumor. •• These lesions can present as progressive bulging of the affected orbit with or without changes in vision.

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•• Hemangiomas are often amenable to surgical therapy due to the presence of a pseudocapsule. •• On MRI, lesions are T2 hyperintense, well-marginated, ovoid, or round that demonstrate contrast enhancement.

■■ Other Imaging Findings •• CT will also demonstrate a contrast-enhancing mass, typically intraconal in location.

� Pearls & � Pitfalls ÛÛ Most common primary adult orbital tumor. ÚÚ Other intraconal lesions, as noted above, may have a similar appearance.

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Case 44

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■■ Clinical Presentation A 62-year-old man presents with sinus congestion, toothache, facial pain, and trismus.

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■■ Imaging Findings

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■■ Differential Diagnosis •• Sinonasal squamous cell carcinoma: Large, irregular, moderately enhancing right maxillary mass with intermediate T2 signal extending into right nasal cavity and ethmoidal sinus with extensive bony destruction and extension into masticator space, buccal space, and soft tissue of the cheek. •• Fungal sinusitis: Low T2 signal locally aggressive destructive mass is generally seen in immunocompromised patients and progresses rapidly. Intracranial or orbital extension with invasion of cavernous sinus is more frequent. •• Non-Hodgkin lymphoma: Previously known as midline granuloma. Low T2 signal and locally aggressive behavior make it difficult to differentiate from sinonasal squamous cell carcinoma. Perforation of nasal septum is very common.

■■ Essential Facts •• Due to malignant neoplasm arising from sinus surface epithelium into sinus lumen. •• It is the most common malignant neoplasm of sinonasal area and accounts for ~80% of sinonasal malignancies. In descending order, maxillary, nasal cavity, ethmoidal, frontal, and sphenoidal sinuses are normal. •• Most common symptom is chronic sinusitis. Other symptoms include unilateral nasal obstruction, epistaxis, and cheek paresthesias. Tooth pain, proptosis, headaches, and trismus may be present due to local tumor spread. •• Generally seen in elderly men. There is no association with history of smoking.

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C

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(A) Moderately enhancing aggressive soft tissue mass at right maxillary sinus with destruction of medial and posterior wall of right maxilla extends into masticator space (arrow), involving the pterygopalatine fossae (arrow), pterygoid muscles (arrow), and nasopharyngeal lumen (arrow). (B–D) Low T1 and intermediate T2 signal mass exhibits patchy postcontrast enhancement. Local infiltration of right temporalis muscle is more apparent. (E) Invasion of the hard palate (arrow), floor of maxillary sinus (arrow) with extension into buccal space (arrow), and into the soft tissue of the cheek (arrow) is seen.

•• Depending on the extent of tumor, the maximal possible surgical dissection and radiation are the preferred treatments. Neck dissection and radiation are performed to treat possible metastatic lymph nodes.

■■ Other Imaging Findings •• On CT scan, unilateral sinonasal soft tissue mass with patchy postcontrast enhancement, destruction of the bony wall of sinus, and aggressive regional spread is seen. •• On MRI, a low to intermediate T1 and T2 signal mass with moderate postcontrast enhancement is seen. Retained secretions exhibit low T1 and high T2 signal. •• Fat-saturated T1-weighted postcontrast imaging helps evaluation of perineural spread, especially in pterygopalatine fossa. •• Possible extension into adjacent orbital cavity, masticator space, hard palate, maxillary alveolar ridge, buccal space, and subcutaneous tissues of the cheek and foramen rotundum as well as possible locoregional lymph node enlargement must be evaluated on the presurgical MRI.

� Pearls & � Pitfalls ÛÛ A moderately enhancing, irregular, aggressive sinonasal

soft tissue mass, more likely seen at maxillary sinus with destruction of sinus wall and possible local invasion in elderly male. ÚÚ Differentiation from sinonasal undifferentiated carcinoma and lymphoma may be difficult solely on imaging findings.

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Case 45

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■■ Clinical Presentation A 30-year-old man presents with a neck lump.

■■ Further Work-up An additional test was performed.

B

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■■ Imaging Findings

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■■ Differential Diagnosis •• Paraganglioma (carotid body tumor): Most likely lesion due to the location within the carotid space at the bifurcation (splaying the internal/external carotid arteries) as well as the vascular nature of the lesion with internal flow voids. •• Jugular schwannoma: Second on the differential list. Although these lesions enhance, flow voids and arterial-like enhancements are not seen. It does not splay the internal/external carotids. •• Lymphadenopathy: As in schwannoma, it is unlikely due to the location between the arteries, arterial nature of the enhancement, and the flow voids.

■■ Essential Facts •• Paragangliomas are slow growing, rather vascular tumors found along the expected location of the vascular chemoreceptor “glomus bodies,” typically within the middle ear (glomus tympanicum), jugular fossa (glomus jugulare), and carotid bifurcation (carotid body tumors). •• Carotid body tumors are usually non–catecholaminesecreting tumors that come to attention due to local effects, presenting as a neck mass and/or with lower cranial nerve palsies. •• Such tumors are bilateral in 5% of cases and malignant in 5 to 10%.

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(A) Axial contrast-enhanced CT scan reveals an intensely enhancing mass along the right carotid space (arrow), which splays the right internal carotid artery (circle) and external carotid artery (arrowhead). (B–D) Multiple MRIs (T1 precontrast [B], T2 [C], and T1 postcontrast with fat saturation [D]) again demonstrate an enhancing mass lesion between the internal and external carotid arteries (large arrows). Multiple small flow voids are present (small white arrows).

•• Imaging demonstrates a rather vascular tumor, with flow voids on MRI. Classic “salt-and-pepper” appearance can be seen with larger tumors. •• “Pepper” represents small T2 flow voids, whereas “salt” are areas of small hemorrhage which are hyperintense on precontrast T1 images. •• Carotid body tumors usually splay the internal and external carotid arteries. •• Treatment is usually a combination of embolization (to devascularize the lesion) as well as surgical resection.

■■ Other Imaging Findings •• Conventional angiography can be used to assess for vascular supply and drainage. Preoperative embolization can also be performed.

� Pearls & � Pitfalls ÛÛ Flow voids on T2 images and arterial-like enhancement on CT suggest the diagnosis.

ÛÛ Carotid body tumors tend to splay the internal/external carotid arteries at the bifurcation.

ÚÚ Hypervascular lymph nodes can have similar appearance but do not occur within the bifurcation.

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Case 46

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■■ Clinical Presentation A 62-year-old man presents with pain and swelling under the right side of the jaw.

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(A) Intensely enhancing soft tissue mass of right lateral tongue (arrows), which does not cross the median raphe. (B) A large irregular necrotic level 1 lymph node with ring enhancement (arrows).

■■ Differential Diagnosis •• Squamous cell carcinoma of oral tongue: Heterogeneously enhancing, irregular, right lateral tongue mass with large necrotic metastatic locoregional lymph node. •• Squamous of carcinoma of lingual tonsil: More commonly seen at the base of the tongue but may extend into oral tongue. Infiltration into floor of mouth is more common. •• Venous malformation of tongue: Irregularly enhancing vascular lesion associated with calcified phleboliths and areas of serpentine enhancement.

■■ Essential Facts •• Malignant neoplasm arising from the superficial squamous epithelium of the freely mobile anterior two-thirds of the tongue. Lateral margin of the tongue is more commonly affected than the undersurface or the tip of the tongue. •• There is a strong association with smoking, alcohol, tobacco chewing, betel nut chewing, and paan chewing. •• Commonly seen in elderly population with male predominance. •• Most common presentation is pain and nonhealing ulcer of the tongue. Occasional bleeding is possible. •• Treatment is surgical resection with or without radiation.

helps detect possible invasion of mandible. Artifacts from dental hardware sometimes make diagnoses with CT scan very difficult. •• On MRI, low T1 and high T2 signal mass with mild to moderate enhancement is seen. Fat-saturated T2-weighted and postcontrast T1-weighted sequences have better sensitivity. •• Presence of metastatic deposit to locoregional lymph node at the time of diagnosis is very common. •• Low volume superficial lesions are best evaluated clinically. The role of imaging is more for staging than for diagnosis. •• MRI is better suited due to better soft tissue contrast, direct coronal imaging, less dental artifacts with staging and evaluation of possible infiltration into oral cavity.

� Pearls & � Pitfalls ÛÛ It is important to evaluate possible extension to con-

tralateral side, invasion of the floor of the mouth, and metastatic deposits to locoregional or distal lymph nodes. ÚÚ For assessment of mucosal extent, clinical evaluation with palpation is more sensitive than imaging. However, for evaluation of deeper extent, invasion of adjacent soft tissue, and staging of lymph nodes, imaging has an important role to play.

■■ Other Imaging Findings •• On CT, an enhancing superficial mucosal lesion is seen. Evaluation of the deeper invasion is better evaluated on coronal reconstructions. Evaluation of bone windows

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Case 47

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■■ Clinical Presentation An 82-year-old woman presents with pulsatile tinnitus and bilateral throat masses on endoscopic exam.

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■■ Imaging Findings

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(A–C) Bilateral arterial structures are noted in the retropharynx, namely the left common carotid artery (arrow) and the right internal carotid artery (arrowheads).

■■ Differential Diagnosis •• Retropharyngeal internal/common carotid arteries: Essentially, this arterial variant is the only diagnosis. However, vascular tumors or malformations could occur along aberrant or normally positioned arteries and, if large enough, could cause an impression along the mucosal surface.

•• Radiographically, CTA (or less commonly MRI/MRA) can be helpful for tinnitus evaluation, particularly with regard to vascular tumors/malformations, atherosclerosis, and other neck masses. •• In this case, the vessels were coursing medially resulting in the “retropharyngeal masses,” representing a common variant.

� Pearls & � Pitfalls ■■ Essential Facts •• Pulsatile tinnitus is a common complaint, with a myriad of etiologies, including pseudotumor cerebri, vascular tumors, atherosclerosis, and vascular malformations.

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ÛÛ CTA can be a good screening tool in patients with pulsatile tinnitus, as noted above.

ÚÚ Such variants must be highlighted to avoid a potentially disastrous biopsy.

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Case 48

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■■ Clinical Presentation A 60-year-old man presents with right-sided submandibular swelling that is tender on palpation.

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■■ Imaging Findings

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(A–D) Enlargement of the right submandibular gland (arrow) with low T1 and intermediate to high T2 signal exhibits moderate postcontrast enhancement. (E) The lesion is more conspicuous (arrow) on fat-saturated postcontrast T1 axial imaging.

■■ Differential Diagnosis

■■ Other Imaging Findings

•• Submandibular gland carcinoma: Enlarged right submandibular gland with low T1 and intermediate to high T2 signal with moderate heterogeneous postcontrast enhancement is seen. There is no evidence for pericapsular stranding or enlargement of submandibular duct. •• Submandibular gland sialoadenitis: Enlarged, intensely enhancing submandibular gland with presence of a calculus and/or dilatation of Wharton’s duct. •• Benign mixed tumor of submandibular gland: Welldefined, ovoid, high T2 signal, moderately enhancing submandibular gland mass.

•• On CT, asymmetric enlargement of submandibular gland with moderate, heterogeneous contrast enhancement is seen. •• On MRI, low to iso T1 signal and intermediate through high T2 signal mass with heterogeneous moderate to intense contrast enhancement is seen. Low T2 signal is seen in high-grade tumors. •• On ultrasound, ill-defined hypoechoic lesion is seen within the submandibular gland. •• On FDG-PET, low metabolic activity is generally seen, unless it is a high-grade mass.

■■ Essential Facts

� Pearls & � Pitfalls

•• It is a primary malignancy of submandibular gland; most commonly adenoid cystic carcinoma or mucoepidermoid carcinoma. •• Generally seen in the middle-aged to elderly population. •• Most common presentation is painless mass of submandibular gland. Other symptoms include paraesthesias or weakness of chin and lower lip. •• Total surgical resection with or without radiotherapy is preferred treatment.

ÛÛ It is important to differentiate a submandibular mass

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from enlarged level 1 lymph node.

ÚÚ Sometimes, primary neoplasms of submandibular gland have very subtle findings on CT scan. Ultrasound or MRI are recommended when findings on CT scan are equivocal.

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Case 49

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■■ Clinical Presentation A 53-year-old man presents with headache.

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■■ Imaging Findings

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(A–C) Multiple MRIs were obtained, including axial T1 pre- and postcontrast (A, B) and T2-weighted images. There is a contrast-enhancing, large, extraaxial mass lesion along the right cerebellopontine angle (CPA) (arrows). The lesion demonstrates T2 hypointensity and results in significant mass effect on adjacent structures.

■■ Differential Diagnosis •• Meningioma: Given a CPA lesion with T2 hypointensity and contrast enhancement, this is the most likely diagnosis. •• Schwannoma: Usually related to cranial nerve VIII and is typically situated within the internal carotid artery extending medially into the posterior fossa. •• Lymphoma: Lymphoma involving the dura can appear as a T2 hypointense lesion. However, a singular lesion of such size would be unusual.

■■ Essential Facts •• Meningiomas are common extra-axial mass lesions believed to arise from arachnoid cap cells. They can occur anywhere along the neural axis. •• CPA meningiomas may present with such symptoms as headache, dizziness, or hydrocephalus due to obstructive mass effect against the posterior fossa structures and fourth ventricle.

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•• Lesions are typically benign, but malignant meningiomas do occur. •• CT may demonstrate a somewhat iso- or hyperattenuating lesion with or without calcifications. •• MRI may demonstrate T2 hypointensity due to relative increased cellularity of the tumors. A dural “tail” may be also be seen, suggesting but not ensuring the diagnosis.

� Pearls & � Pitfalls ÛÛ Most common extra-axial tumor. ÛÛ In the CPA, the differential traditionally also includes epidermoids, arachnoid cysts, and aneurysms.

ÚÚ Radiographic appearance does not correlate well with the histological grade or aggressiveness of the tumor.

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Case 50

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■■ Clinical Presentation A 60-year-old presents with painless swelling on the left side of the neck.

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■■ Imaging Findings

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(A) Contrast-enhanced CT shows a large, rounded, heterogeneously enhancing mass (arrow) on the left at level 2, at the level of the angle of the mandible and anterior to the sternocleidomastoid. The mass exhibits pericapsular stranding, compatible with pericapsular spread. Another enlarged lymph node, seen at left level 2, exhibits irregular intranodal necrosis. A few scattered lymph nodes on the right exhibit fatty hilum, ovoid, and kidney shape, with caliber , 1 cm. (B) There is effacement of the left glossotonsillar sulcus with presence of a small soft tissue mass (arrow).

■■ Differential Diagnosis

■■ Other Imaging Findings

•• Nodal squamous cell carcinoma: Presence of heterogeneously enhancing rounded mass with pericapsular stranding and another enlarged rounded mass with central necrotic changes at left level 2 are compatible with metastatic malignant lymph nodes. There is effacement of the left glossotonsillar sulcus with this soft tissue mass which turned out to be carcinoma of the base of the tongue. •• Second branchial cleft cyst: Single cystic mass is seen at the level of the angle of the mandible and anterior to the sternocleidomastoid. There is no presence of a soft tissue nodule and the enhancing wall is thinner. Pericapsular stranding can be seen only if it is infected and, in that case, it is tender and painful. It is generally seen in a younger age group and without evidence for any primary neoplasm. •• Non-Hodgkin lymphoma: Generally bilateral, large, nonnecrotic lymph nodes are seen without evidence for primary tumor. NHL tends to be aggressive with involvement of tonsils and it can be necrotic.

•• The size criteria: •• For level 1 and 2 lymph nodes, . 1.5 cm •• Other levels, . 1.0 cm •• The shape criteria: •• Round or oval configuration •• Loss of normal kidney shape •• Loss of fatty hilum •• The morphology criteria: •• Central inhomogeneous matrix •• Necrotic nodes •• Areas of calcification •• Pericapsular stranding •• Both CT and MR can discern the size, shape, or morphologic findings. The inhomogeneity of internal matrix following contrast enhancement is better visualized on MRI. •• FDG-PET exhibits increased metabolic activity and metastatic lymph nodes and is considered to be more sensitive than CT or MRI.

■■ Essential Facts

� Pearls & � Pitfalls

•• Primary head and neck squamous cell carcinoma spreads to locoregional lymph nodes, creating metastatic intranodal squamous cell carcinoma. In 10% of the cases, the primary is occult and nodal squamous cell carcinoma is primary presentation. •• Nodal squamous cell carcinoma is more common in the nasopharynx, oropharynx, oral cavity, and hypopharynx than in supraglottic, glottis, and subglottic regions. •• The clinical presentation is firm to hard, nontender, painless masses. •• For nodes , 1 cm in size, radiation alone is preferred. For larger nodes, surgical excision along with resection of primary tumor is performed.

ÛÛ Detection of malignant lymph nodes is very important

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for primary TNM staging. Detection of nodal malignancy in posttreatment studies is important for prognostic information and denotes failure of local tumor control. ÚÚ Suppurative adenitis can mimic malignant lymph node. ÚÚ Although the size, shape, and morphologic criteria for malignant lymph nodes increase the sensitivity and specificity of imaging studies, they cannot detect microscopic malignant involvement of lymph nodes.

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Case 51

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■■ Clinical Presentation A 6-month-old infant presents with a bump on the nose. There is no history of trauma.

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Contrast-enhanced axial CT images were obtained through the maxillofacial bones in soft tissue (A) and bone windows (B). There is a small fat attenuation lesion along the nasion (arrow) with mild underlying bony flattening (arrowhead).

•• Nasal dermoid: In a young child, this is the most likely diagnosis given the fat attenuation, location along the upper nose, and the underlying bony changes. •• Sebaceous cyst: Can appear similarly but is unusual to see in a young child in this particular location. •• Venolymphatic malformation: Can appear as a cystic lesion but not of fat attenuation.

•• CT and MRI are often complementary in diagnosis. CT will show the fat attenuation lesion, whereas MRI may better demonstrate sinus tract and any intracranial extension if present. •• Intracranial extension of any of these malformations must be evaluated as treatment is surgical. On CT, intracranial involvement may manifest as an enlarged foramen cecum or bifid crista galli. MRI may better demonstrate soft tissue along an expected tract.

■■ Essential Facts

� Pearls & � Pitfalls

•• Nasal dermoids are along a spectrum of anomalies involving the anterior neuropore that can be seen in this region, which also includes sinus tracts, nasal encephaloceles/ meningoceles, and nasal gliomas (trapped brain tissue). •• Some lesions may remain clinically silent until 2nd or 3rd decade of life depending on the location and amount of tissue present. •• Dermoids usually present in the infant population due to cosmetic change noted along the nasion.

ÛÛ Age, location, and fat attenuation of this focus strongly

■■ Differential Diagnosis

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suggest the diagnosis.

ÚÚ Evaluating the cribriform plate and crista galli can be

difficult, as there is a limited degree of ossification in the infant age group. ÚÚ Evaluation for intracranial extension of such lesions is, however, essential for surgical planning.

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Case 52

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■■ Clinical Presentation A 41-year-old presents with enlarging painless right submandibular mass.

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■■ Imaging Findings

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(A–C) Contrast-enhanced CT scan reveals enlarged, lobulated right submandibular gland with presence of a low attenuating mass (arrow) with moderate contrast enhancement.

■■ Differential Diagnosis

■■ Other Imaging Findings

•• Submandibular gland benign mixed tumor: Enlarged right submandibular gland with lobulated contour is seen. There is presence of a large low attenuating lesion within a moderately enhancing submandibular gland. •• Submandibular gland mucocele: Unilocular fluid-filled intraglandular lesion is seen without any contrast enhancement. •• Submandibular gland sialadenitis: Intensely enhancing enlarged submandibular gland is seen in the acute phase with and without calcification. It is almost always painful with acute onset. In chronic phase, an atrophic gland without significant enhancement is seen.

•• On CT, a well-defined all-lobulated submandibular gland mass with cystic changes in larger lesions can be seen with and without calcification. Mild to moderate contrast enhancement is seen. •• On MRI, smaller masses displayed low T1 and high T2 signal with intense homogeneous postcontrast enhancement. Larger masses tend to be heterogeneous with high T2 signal necrotic areas within low T2 signal capsule, low T2 signal foci of calcification, and heterogeneous postcontrast enhancement. •• On ultrasound, well-defined solid mass is seen. Areas of necrosis and calcification may be seen in larger masses. •• On FDG-PET, increased metabolic activity is seen even though it is a benign tumor.

■■ Essential Facts •• It is the most common neoplasm of the submandibular gland. It is a well-defined benign mass of epithelial, stromal, and myoepithelial complements. •• Most common presentation is as a slow growing, painless submandibular space mass. Generally well demarcated, it can be lobulated and somewhat heterogeneous. •• The highest incidence is in middle age. •• Total surgical excision with intact fibrous capsule is the preferred treatment. Seeding of biopsy tract or surgical rupture can result in seeding with potential for multifocal recurrence. •• Can undergo malignant transformation if left untreated.

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� Pearls & � Pitfalls ÛÛ It is important to differentiate a submandibular mass from an enlarged level 2 lymph node.

ÚÚ If findings on noncontrast enhanced CT scan are

equivocal, further evaluation with ultrasound on MRI is recommended.

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Case 53

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■■ Clinical Presentation A 53-year-old man presents with vision problems and headaches.

■■ Further Work-up An additional imaging test was performed.

D

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■■ Imaging Findings

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B

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E

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(A–C) Noncontrast head CT in brain (A, B) and bone (C) windows demonstrates a heterogeneous lesion involving the posterior aspect of the sella turcica and top of the clivus. There are areas of calcification (black arrowheads) and areas that appear of low attenuation (white arrowhead). (D–F) Multiple MRIs were obtained including sagittal T1, axial T1 postcontrast with fat suppression, and axial T2-weighted images. There is a mass lesion of the top of the clivus with contrast enhancement and T2 prolongation (arrows).

■■ Differential Diagnosis •• Clival chordoma: T2 hyperintense, enhancing lesion arising from the clivus could most certainly represent a chordoma. •• Chondrosarcoma: Could also be T2 hyperintense, but these lesions tend to be more often associated with the petroclival fissure, off the midline in a parasagittal location. •• Craniopharyngioma: Could also present as a heterogeneous lesion with calcification. However, they are usually centered anteriorly and superiorly within the suprasellar cistern.

•• Clival tumors can be seen in any age group and can present with several symptoms, including headache, visual changes, and cranial nerve palsies. •• Most lesions are difficult to treat entirely with surgery and thus radiation therapy is often also used. •• Outlook is guarded, with some lesions behaving in an indolent manner, whereas others grow quickly. •• On CT, clival chordomas often present as large expansile soft tissue tumors with or without calcification. •• MRI typically demonstrates lesions with T2 prolongation and areas of heterogeneous enhancement.

� Pearls & � Pitfalls

■■ Essential Facts

ÛÛ T2 hyperintensity of a midline clival mass suggests this

•• Chordomas are uncommon tumors that arise from notochordal remnants along the neural axis. Clival chordomas are second only to sacral chordomas in frequency.

ÚÚ Chondrosarcomas can have similar T2 hyperintensity,

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diagnosis.

but tend to be located in a parasagittal distribution.

ÚÚ Mapping of tumor extent is vital for surgical planning.

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Case 54

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■■ Clinical Presentation A 52-year-old woman presents with dryness of eyes and mouth with painless swelling of right parotid gland.

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■■ Imaging Findings

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(A–C) Contrast-enhanced CT shows increase in caliber of right parotid gland with cystic areas of varying sizes (arrows) within bilateral parotid parenchyma. Smaller cysts are also seen along the left parotid duct (arrow). Punctate calcifications (arrow) with mild atrophic changes (arrow) are seen on the left side. Smaller solid nodules are also seen at right parotid gland. There is mild heterogeneous enhancement of the rest of the bilateral parotid parenchyma.

■■ Differential Diagnosis •• Sjögren syndrome: Enlargement of right parotid gland with presence of multiple cystic areas of varying size within right parotid parenchyma with a few smaller solid areas and heterogenous contrast enhancement in postmenopausal woman. The right parotid gland is likely in acute phase, whereas the left appears to be in chronic phase with areas of punctate calcification and loss of volume. Smaller cystic collections along the left-sided Stensen’s duct likely represent focal stenoses and dilatation. •• Benign lymphoepithelial cysts: Mixed cystic and solid nodules are seen within enlarged bilateral parotid glands. There is positive history of HIV infection. It is generally associated with enlarged neck lymph nodes and tonsillar prominence. •• Chronic parotitis: It may be postinfectious or postobstructive. Multiple calcific calculi are seen with irregular dilatation and stenosis of parotid ducts. There is lack of the solid parotid nodules.

■■ Essential Facts •• It is a chronic autoimmune disease resulting in salivary and lacrimal gland tissue destruction. The primary form is associated with unknown immune-mediated etiology, with possible preceding viral infection. The secondary form is generally associated with collagen vascular disease and rheumatoid arthritis or systemic lupus erythematosus. •• It is a slowly progressive condition that matures over the years and is commonly seen in middle-aged to elderly, commonly menopausal women. •• Most common clinical presentation is firm swelling of both the parotid glands. When associated with collection vascular disease, dryness of eyes, mouth, and skin is also present.

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•• There is a known association with non-Hodgkin lymphoma within parotid glands or GI tract. •• A diagnosis is made with positive labial biopsy and presence of auto antibody against Sjögren antigen A or B. •• Treatment is only symptomatic.

■■ Other Imaging Findings •• On CT scan, bilateral enlarged parotid glands are seen with multiple cystic and solid areas within parotid parenchyma. The microcystic areas can evolve into macrocystic changes. Areas of punctate calcifications may or may not be present. •• On MRI, bilateral diffuse low T1 and high T2 signal cystic areas are seen within the bilateral parotid parenchyma. The size can vary from 1 to 2 mm to large cysts. There is heterogenous, mild to moderate enhancement of the parotid parenchyma contrasted against the nonenhancing cystic areas. •• On ultrasound, the intraparotid cysts are detected only if they are larger than 2 mm. Increased vascularity is seen on color Doppler. •• On sialography, there are foci of stenosis and dilatation within the parotid duct. The intraglandular branches may exhibit stenosis or truncation of branches with areas of focal fluid collection. MR sialography is increasingly replacing conventional sialography.

� Pearls & � Pitfalls ÛÛ MRI with MR sialography is preferred imaging technique if Sjögren syndrome is suspected clinically.

ÚÚ Presence of locally aggressive infiltrative margins, large solid masses that represent lymphoid collection with cervical lymphadenopathy raise the possibility of malignant transformation.

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Case 55

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■■ Clinical Presentation A 47-year-old woman presents with history of prior neck surgery. Patient now presents with complaint of stringlike neck lump.

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■■ Imaging Findings

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(A, B) Contrast-enhanced axial CT images were obtained through the neck. The right internal jugular vein does not opacify (arrow). Adjacent soft tissue infiltration is noted along with several surgical clips.

■■ Differential Diagnosis •• Jugular vein thrombosis: This is the most obvious choice, as the internal jugular vein is not visualized adjacent to the common carotid artery. •• Necrotic lymph node: May also present as a lump. Given postsurgical nature of the neck, this is a decent second possibility. However, one would expect to see a low attenuation center with some degree of enhancement. •• Common carotid artery thrombosis: The affected vascular structure is too lateral to represent the artery.

■■ Essential Facts •• Jugular venous thrombosis is an underappreciated phenomenon that can be seen in the setting of central venous lines, prior neck surgery, neck malignancy, or neck infection. •• Any factor that affects Virchow’s triad (endothelial disruptions, intrinsic blood clotting changes, slow blood flow) can lead to thrombosis. •• Jugular vein thrombosis associated with oropharyngeal infections is termed Lemierre syndrome.

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•• Treatment is directed at an underlying infection, if present. The use of anticoagulation is debated due to the relatively low incidence of pulmonary emboli in comparison to lower extremity thromboses. •• CT may demonstrate lack of normal venous filling in association with adjacent inflammatory changes if infection is present.

■■ Other Imaging Findings •• Normal venous flow void may be absent on MRI. Contrast-enhanced images may show perivascular enhancement, if infection is present.

� Pearls & � Pitfalls ÛÛ Always evaluate the vasculature on contrast-enhanced neck CT exams.

ÚÚ Underdiagnosed entity, as noted above. Always check for adjacent inflammatory changes.

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Case 56

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D

■■ Clinical Presentation A 48-year-old man presents with history of chronic sore throat and recent aspiration.

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■■ Imaging Findings

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■■ Differential Diagnosis •• Supraglottic squamous cell carcinoma of epiglottis: Moderately enhancing soft tissue mass involving epiglottis and left aryepiglottic fold, likely infiltrating the left thyroid cartilage, is seen in a man with history of smoking. •• Laryngocele: A cystic mass in paraglottic space or extra laryngeal space is seen causing soft tissue distortion and variable obstruction. •• Adenoid cystic carcinoma of larynx: A rare submucosal mass of supraglottic larynx; it can be indistinguishable on imaging from supraglottic squamous of carcinoma.

■■ Essential Facts •• It is a primary squamous cell carcinoma originating from the mucosal folds above the true vocal cords including epiglottis, aryepiglottic folds, preepiglottic and paraglottic spaces, and false vocal cords. •• The most common presentation is in middle-aged to elderly men. There is a close association with history of alcohol and tobacco use. •• The most common clinical presentation is chronic sore throat with dysphagia, hoarseness of voice, and ear pain. •• The supraglottic larynx is rich in lymphatics, resulting in early metastatic disease. About 30 to 35% of the patients have nodal disease at the time of presentation. •• Speech preserving partial laryngectomy or laser resection with partial laryngectomy is performed in smaller masses with low staging. In cases with involvement of true vocal

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B

D

(A–C) A moderately enhancing large soft tissue mass (arrow) is seen involving the epiglottis and left aryepiglottic fold. The mass is in close proximity to left thyroid cartilage and likely infiltrates it. (D) The true vocal cords appear to be free of the mass.

cord, chemotherapy and radiation therapy is performed. Total laryngectomy is performed in cases with extralaryngeal spread or thyroid cartilage involvement.

■■ Other Imaging Findings •• On CT scan, moderately enhancing soft tissue mass is seen involving the epiglottis, aryepiglottic fold, or false vocal cord. Sagittal reconstruction is helpful to evaluate invasion of preepiglottic space. The carcinoma of aryepiglottic fold can involve the pyriform sinus or false vocal cord. Paraglottic extension is possible in tumors involving the false vocal cord. •• On MRI, a low to intermediate signal and intermediate T2 signal mass exhibits moderate homogenous postcontrast enhancement. Enhancement of cartilage similar to the mass signifies tumor invasion. •• On FDG-PET, increased metabolic activity is seen. However, the utility of this technique is mainly for nodal staging and postsurgical follow-up.

� Pearls & � Pitfalls ÛÛ The diagnosis is apparent on clinical criteria and

endoscopic findings. The goal of imaging is to evaluate infiltration of deeper structures and staging. ÚÚ Sometimes the mucosal extent of the tumor is underestimated on imaging. Knowledge of the endoscopic findings is very helpful in imaging assessment.

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Case 57

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■■ Clinical Presentation A 17-year-old boy presents with abrupt right-sided weakness after a recent football game.

■■ Further Work-up

B

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C

D

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■■ Imaging Findings

A

B

C

D

(A) Noncontrast brain CT demonstrates a subacute infarct involving the left basal ganglia (curved arrow). (B–D) CT angiogram of the neck was also performed and shows a focal area of luminal narrowing involving the left internal carotid artery (ICA) (B, D, arrows), which has a normal lumen distally (C, circle). The right ICA is unremarkable (B, C, arrowheads).

■■ Differential Diagnosis

■■ Other Imaging Findings

•• Left ICA dissection: Most likely diagnosis, given the young patient age, history of likely neck manipulation, and otherwise clean appearance of the remaining neck vasculature. •• Atherosclerotic disease: Unlikely to present as a focal lesion in an otherwise normal cervical arterial vasculature; unusual age range unless other comorbidities are present. •• Vasculitis: Large vessel arteritis, such as Takayasu, could have a similar appearance of narrowing. However, constitutional symptoms often precede the occlusive phase of the disease, not congruent with our current scenario.

•• In a young patient population, CTA is a quick, reliable method of evaluating the cervical vasculature. Vessel abnormalities, such as focal narrowing, occlusion, and pseudoaneurysm formation, are easily seen. •• MRI/MRA is also quite effective in evaluating such patients. Fat-saturated images through the neck can assess for methemoglobin, and diffusion-weighted brain imaging can evaluate for ischemic cerebral infarction during the same exam. •• In certain situations, conventional angiography can be of value to assess for subtle contour abnormalities.

■■ Essential Facts •• Cervical arterial dissection is a common cause of reversible and nonreversible cerebral ischemic events in the younger population. •• Presenting signs and symptoms vary from devastating neurovascular compromise to neck pain to no symptoms at all. Thus, a high index of suspicion is necessary in evaluating such patients. •• There is an increased risk of cervical arterial dissection in patients with connective tissue disorders, smoking, hypertension, and neck injury (even minor). •• Mainstay of therapy is anticoagulation with follow-up imaging to ensure vessel healing. Interventional therapies may be warranted if medical management fails or if there is extensive vessel damage.

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� Pearls & � Pitfalls ÛÛ CTA, particularly in the younger patient population,

is a quick, reliable method to assess the cervical vasculature. ÚÚ Dissection can be occult on any one or more imaging methods. Therefore, if suspicion remains high and test results are inconclusive, try another method. ÚÚ Conventional angiography remains the gold standard for detection of dissection.

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Case 58

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■■ Clinical Presentation A 65-year-old man presents with dysphagia.

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■■ Imaging Findings

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(A–C) A bulky moderately enhancing soft tissue mass infiltrates the cricoid cartilage (arrow) causing sclerosis of left arytenoid cartilage (arrowhead) and erosion of right arytenoid cartilage (small arrow). There is patchily enhancing mild nodularity of left true vocal cord, suggesting that spread.

■■ Differential Diagnosis •• Subglottic squamous cell carcinoma: A bulky soft tissue mass centered in the region of cricoid cartilage resulting in infiltration and destruction with involvement of arytenoid cartilages. There is involvement of posterior commissure. Nodularity of left true vocal cord is compatible with direct spread of tumor. •• Chondrosarcoma of larynx: A primary soft tissue neoplasm centered in cricoid or thyroid cartilage. Areas of typical chondroid calcification are seen. •• Adenoid cystic carcinoma of larynx: A very rare tumor, it can be confused with subglottic squamous cell carcinoma on imaging.

■■ Essential Facts •• It is a primary squamous cell carcinoma originating from mucosal surface of subglottis—extending from the inferior margin of true vocal cords to the lower border of cricoid cartilage. •• Most common presentation is in middle-aged to elderly men. There is significant association with smoking or alcohol abuse. •• Most common clinical presentation is dyspnea, stridor, and hoarseness of voice. •• It is the least common of laryngeal squamous cell carcinoma and represents only 5% of the cases. •• The subglottic larynx is relatively avascular and alymphatic, and hence metastatic lymph nodal involvement occurs at a later stage. However, the clinical course is

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relatively silent with the result that the tumor is relatively advanced at the time of diagnosis with possible invasion of surrounding structures. •• For large tumors, total laryngectomy with radiation therapy is performed.

■■ Other Imaging Findings •• On CT, an enhancing soft tissue mass causing narrowing of the subglottic lumen is seen. Infiltration and destruction of cricoid cartilage is common. Involvement of posterior commissure and arachnoid cartilages is also common. Presence of lymph nodes is unusual at the time of diagnosis. Level III, level IV, and paratracheal lymph nodes are more commonly involved. •• On MRI, low to intermediate T1 signal and intermediate T2 signal mass in the homogeneous contrast enhancement is seen. Enhancement of cartilage indicates tumor infiltration. •• On FDG-PET, intense metabolic activity is seen.

� Pearls & � Pitfalls ÛÛ It is difficult to differentiate subglottic spread of pri-

mary glottic laryngeal squamous cell carcinoma from a primary subglottic squamous cell carcinoma spreading into glottic larynx. ÚÚ The prognosis is less favorable because of advanced disease at the time of diagnosis.

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Case 59

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■■ Clinical Presentation A 7-year-old girl presents with progressive bulging eye.

■■ Further Work-up An additional test was obtained.

C

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D

E

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■■ Imaging Findings

A

B

D

C

E

(A, B) Contrast-enhanced CT images in soft tissue and bone windows demonstrate a right orbital extraconal lesion with solid and cystic components (circle) and some adjacent mild bony remodeling (arrowhead). (C–E) MRI ([C] axial T1 precontrast with fat suppression, [D] postcontrast with fat suppression, [E] FLAIR) shows the lesion to be enhancing with smaller cystic foci (large arrows). A fluid–fluid level is also observed (small arrows).

■■ Differential Diagnosis •• Orbital lymphangioma: An orbital lesion with an internal fluid–fluid level in a pediatric patient suggests this diagnosis. •• Orbital capillary hemangioma: Typically found in patients younger than 2 years of age and usually involutes over time, similar to other infantile hemangiomas; no fluid–fluid level. •• Orbital phlegmon: Typically, the patient is quite ill and the adjacent ethmoid or frontal sinuses are opacified.

■■ Essential Facts •• Orbital lymphangiomas are similar histologically to other congenital venolymphatic malformations of the head and neck and contain variable amounts of venous and lymphatic tissues. •• Orbital lesions may remain clinically silent until an upper respiratory infection or other inflammatory process causes expansion. •• Lesions can involve any compartment of the orbit and, like in other regions of the head and neck, can be transpatial.

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•• Patients may present with pain, cosmetic deformity, or visual changes depending on the size and location of the lesion. •• Orbital lymphangiomas can have a variety of appearances based on the amount of venous and lymphatic components and are best diagnosed on MRI. •• Lesions are typically ill defined with enhancing portions and cystic areas. Fluid–fluid levels can be present and are particularly helpful in diagnosing such lesions, as they are not typically associated with other masses. •• Treatment usually requires a combination of surgery and sclerotherapy.

■■ Other Imaging Findings •• CT may demonstrate phleboliths (in the venous portions of the lesions) as well as any adjacent bony remodeling.

� Pearls & � Pitfalls ÛÛ Can be associated with other intracranial vascular anomalies.

ÚÚ As with other lymphangiomas of the head and neck, full delineation of the lesion is required for proper work-up.

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Case 60

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■■ Clinical Presentation A 12-year-old child presents with feeling of fullness of throat.

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■■ Imaging Findings

B

A

(A) T1 sagittal image exhibits a low T1 signal midline rounded mass (arrow) at the base of the tongue projecting into vallecula. (B) T2 axial image exhibits a rounded high T2 signal cystic midline mass (arrow) at the tongue base at the expected location of foramen cecum (arrow).

■■ Differential Diagnosis •• Thyroglossal duct cyst: A midline benign cystic mass is seen at the tongue base projecting into the vallecula in a young girl. •• Dermoid of the tongue: It would display a fat or fluid attenuation low-density mass on CT scan. However, hyperintense T1 signal would be seen on MRI in case of dermoid. •• Anterior neck malignant necrotic node: It is rare in children. Necrotic node of delphian chain may mimic an infected thyroglossal duct cyst.

■■ Essential Facts •• It is the most common congenital neck lesion and represents a remnant of the thyroglossal duct. •• It is due to failure of involution of the thyroglossal duct, which extends between foramen cecum of the tongue base and the bed of thyroid gland embryonic age. Persistent secretions of epithelial cells result in the cyst formation. Sometimes, ectopic thyroid tissue is also formed along the course of thyroglossal duct. •• Generally seen in pediatric population but can be found well into middle age. •• The most common clinical presentation is a midline or, less commonly, paramidline neck mass. It can also present as intermittent or recurrent neck swelling, sometimes associated with minor upper respiratory tract infection.

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•• Complete surgical resection, called Sistrunk procedure, includes surgical removal of the cyst and midline portion of hyoid bone with surgical dissection of the duct up to the foramen cecum.

■■ Other Imaging Findings •• On CT, a low attenuating midline neck mass is seen with a thin peripheral rim enhancement. If infected, there may be an irregular thick wall enhancement. The mass can be seen at the expected location of foramen cecum at the base of the tongue, in the vallecula, at the level of hyoid bone, or up to bed of thyroid gland. •• On MRI, a low T1 and high T2 signal cystic mass is most common. If the content includes proteinaceous fluid, it may display high T1 signal. Only thin peripheral rim enhancement is seen on postcontrast imaging unless infected. •• On ultrasound, an anechoic or hypoechoic midline neck mass without internal echoes is seen. •• Nuclear scintigraphy is positive in case of ectopic thyroid gland.

� Pearls & � Pitfalls ÛÛ Location is the most important criteria for diagnosis.

About 50% of these are seen at the level of hyoid bone, 25% at the suprahyoid neck, and 25% at the infrahyoid neck. ÚÚ Rarely, it can be eccentric rather than central in location.

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Case 61

A

■■ Clinical Presentation A 41-year-old woman presents with fullness of the oropharynx.

■■ Further Work-up An additional exam was performed.

B

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■■ Imaging Findings

A

B

C

D

(A) Contrast-enhanced neck CT demonstrates a soft tissue mass that is obliterating the normal left-sided parapharyngeal fat (circle). (B–D) Multiple MRIs were obtained including axial T2 (B), axial T1 (C), and T1 postcontrast with fat suppression (D). The lesion (arrows) demonstrates significant T2 hyperintensity and uniform contrast enhancement.

■■ Differential Diagnosis •• Pleomorphic adenoma: High on the differential list due to T2 prolongation and sharp margins of the lesion. •• Parapharyngeal space schwannoma: Less common lesion in the parapharyngeal space. However, T2 prolongation can also be seen, as in other head and neck schwannomas. •• Other salivary gland tumors: More aggressive lesions can also be found in this space and could appear similarly.

■■ Essential Facts •• Pleomorphic adenomas, also known as “benign mixed tumors,” arise from minor salivary gland remnant tissue found in the parapharyngeal space. •• There is a female predominance, and most lesions are found in adulthood. These tumors are typically benign but can be associated with malignancy in a minority of cases (carcinoma expleomorphic adenoma). •• Such tumors are typically found within the parotid gland but can be seen in any location where salivary gland rests may be.

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•• Parapharyngeal lesions typically present due to mass effect and thus can be quite large at presentation. •• MRI usually demonstrates a well-marginated lesion with uniform contrast enhancement and T2 prolongation.

■■ Other Imaging Findings •• CT can demonstrate a lesion within the parapharyngeal space but has intrinsically less soft tissue differentiation, particularly with regard to tumor extent.

� Pearls & � Pitfalls ÛÛ T2 prolongation suggests the diagnosis of pleomorphic adenoma.

ÚÚ MR characteristics are not definitive and thus all such lesions require resection.

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Case 62

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■■ Clinical Presentation A 42-year-old presents with persistent headache.

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■■ Imaging Findings

A

B

C

(A, B) A low T1 and high T2 signal expansile mass is seen at the right petrous apex (arrow). (C) Restricted diffusion (arrow) is seen at the right petrous apex.

■■ Differential Diagnosis

■■ Other Imaging Findings

•• Congenital cholesteatoma of petrous apex: Low T1 and high T2 signal petrous apex mass with restricted diffusion in pediatric to young adult population. •• Cholesterol granuloma of petrous apex: Expansile lytic petrous apex mass is seen on CT. However, on T1-weighted MRI, hyperintense T1 signal is visualized due to presence of cholesterol. •• Trapped fluid at petrous apex: Expansile lytic petrous apex mass with relative preservation of trabeculae is seen on CT. MRI exhibits low T1 and high T2 signal. However, there is no evidence for restricted diffusion.

•• On CT, a unilateral, expansile, mass of petrous apex with smooth margins and trabecular destruction is seen. It is important to evaluate possible extension into carotid canal, Meckel’s cave, otic capsule, or facial nerve canal. •• On MRI, low to intermediate T1 signal and high T2 signal is seen. No significant contrast enhancement is seen. Restricted diffusion is seen on diffusion-weighted sequence. Relationship with adjacent neural structures like cranial nerves V and VII is better appreciated on MRI. Differentiation from arachnoid cyst, cholesterol granuloma, and trapped fluid collection is better on MRI.

■■ Essential Facts

� Pearls & � Pitfalls

•• It is a solid mass of petrous apex, lined with stratified squamous epithelium. Progressive desquamation of the epithelium results in accumulation of debris made up of keratin and cholesterol crystals. •• The most common clinical presentation is headache. Unilateral sensorineural hearing loss, palsy of cranial nerve VI or VII, vertigo, or trigeminal symptoms may also be present, depending on the extent of the mass. •• Generally, it is detected in young adult to middle-aged populations. •• Complete surgical excision is preferred treatment.

ÛÛ Restricted diffusion on MRI is characteristic. ÚÚ On CT, it may be difficult to differentiate from trapped

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fluid or cholesterol granuloma.

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Case 63

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B

C

■■ Clinical Presentation A 45-year-old woman presents with decreased vision.

■■ Further Work-up An additional test was performed.

D

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■■ Imaging Findings

B

A

C

■■ Differential Diagnosis •• Craniopharyngioma: Common suprasellar lesion, often seen with cystic areas and foci of calcification. •• Germ cell tumor: Less common lesion of the suprasellar cistern; tends to be rather solid. •• Rathke’s cleft cyst: Common suprasellar cystic lesion; does not significantly enhance and usually does not calcify.

D

(A–D) Multiple MRI sequences were obtained— contrast-enhanced T1-weighted images (A, B) and T2-weighted (C) images—along with a noncontrast CT (D). These images demonstrate a partially cystic, rim-enhancing focus within the suprasellar cistern (circles). Peripheral calcifications are present (arrow).

•• On MRI, lesions are often mixed solid and cystic. Solid portions will enhance. MRI demonstrates full extent of tumor as well as effects on adjacent structures. •• CT, however, is often complementary in demonstrating characteristic calcifications (. 80%), thus helping to narrow the diagnosis.

� Pearls & � Pitfalls ÛÛ SATCHMO suprasellar cistern lesion mnemonic:

■■ Essential Facts •• Craniopharyngiomas are benign tumors of the suprasellar cistern derived from craniopharyngeal duct remnants. Adamantinomas and papillary are the two main histologic subtypes. •• Two tumor peaks are seen, one in children and one in adults in their 50s and 60s. •• Patients tend to present with headache as well as visual symptoms related to impingement upon the optic chiasm.

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�

S (sellar tumor) A (aneurysm) � T (teratoma) � C (craniopharyngioma) � H (hypothalamic glioma) � M (meningioma) � O (optic nerve glioma) ÚÚ Craniopharyngiomas can be difficult to differentiate from Rathke’s cleft cyst, particularly if largely cystic. �

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Case 64

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C

D

■■ Clinical Presentation A 50-year-old man presents with hoarseness of voice, dyspnea, and stridor.

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■■ Imaging Findings

A

C

■■ Differential Diagnosis •• Glottic laryngeal squamous cell carcinoma: Irregular bilateral vocal cord mass is seen with paralaryngeal extension, erosion of anterior thyroid cartilage, extralaryngeal spread involving the strap muscles, and subglottic extension in an elderly man with history of smoking and alcohol abuse. •• Wegener granulomatosis of larynx: Marked glottic and supraglottic thickening is seen. It is seen in association with nasal, tracheobronchial, and renal disease. •• Chondrosarcoma of larynx: It is a submucosal mass centered in the thyroid or cricoid cartilage. Areas of typical chondroid calcification are seen.

■■ Essential Facts •• It is a squamous cell carcinoma originating from the mucosal surface of true larynx, including the vocal cord, the anterior commissure, and the posterior commissure. •• The most common presentation is in elderly men. There is a strong association with history of tobacco and alcohol abuse. •• The most common clinical presentation is hoarseness or change in voice. •• The vocal cords of glottic larynx are made up of fibroblastic tissue and are relatively avascular, without rich network of lymphatics. Hence, it is not common to have nodal metastatic disease at the time of diagnosis. •• For smaller T1 stage I tumors, focal laser surgery or radiotherapy alone is performed. For larger and higher

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B

D

(A–C) There is irregular soft tissue with moderate contrast enhancement of the bilateral true vocal cords (arrow) with paralaryngeal extension (arrow) and involvement of anterior commissure (arrow). There is gross erosion of the anterior thyroid cartilages (arrow). There is anterior extralaryngeal spread with infiltration of bilateral strap muscles (arrow). There is also sclerosis of left arytenoid cartilage. Subglottic extension is seen to the base of cricoid cartilage (arrow). (D) A right-sided level 3 lymph node is seen lateral to right jugular vein.

stage tumors, partial or total laryngectomy with or without radiotherapy is performed.

■■ Other Imaging Findings •• On CT, mildly hyperdense nodular or infiltrative mass is seen on the true vocal cord. Possible infiltration of thyroid cartilage is better visualized on CT. •• On MRI, low to intermediate T1 signal and intermediate T2 signal mass with homogeneous postcontrast enhancement is seen on vocal cord. It may be difficult to avoid breathing or swallowing motion–related artifacts on MRI. •• On FDG-PET, increased metabolic activity is seen. •• It is important to look for possible metastatic lymph nodes, supraglottic spread across the laryngeal ventricle, and subglottic spread 1 cm below the free margin of true vocal cord.

� Pearls & � Pitfalls ÛÛ Anterior true vocal cord and anterior commissure are

more likely affected than posterior. An irregular mucosal surface of true vocal cord with moderate contrast enhancement is suspicious for an early squamous cell carcinoma. ÚÚ In case of very small true vocal cord tumors, imaging findings can be very subtle. Correlation with endoscopic findings helps accurate imaging diagnosis.

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Case 65

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■■ Clinical Presentation A 22-year-old woman presents with facial and oral asymmetry.

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■■ Imaging Findings

A

B

(A, B) Contrast-enhanced axial (A) and coronal (B) CT images of the maxillofacial bones. There is a tubular fluid density focus, without associated enhancement, along the floor of the mouth (arrows) within the sublingual space.

•• Ranula: Common, painless lesion due to obstruction of a minor salivary gland with accumulation of secretions; best choice due to tubular nature of the lesion. •• Second branchial cleft cyst: More often found along the submandibular space; would not expect to see such anterior extension. •• Cystic hygroma: Lesions tend to be multilocular and transpatial but could occur in this location.

•• A simple ranula is confined to the sublingual space, representing a retention cyst involving minor salivary gland. •• Diving ranulas extend out of the sublingual space and represent a pseudocyst, often involving the submandibular space. •• On cross-sectional imaging, a thin enhancing wall may be seen. Diving ranulas often have a “tail” extending retrograde to the sublingual space. •• Surgical resection is curative.

■■ Essential Facts

� Pearls & � Pitfalls

•• Ranulas represent accumulated secretions due to obstruction of a minor salivary gland. •• The term derived from the Latin word for frog, presumably due to the similarity in appearance to the floor of the frog’s mouth. •• These lesions typically present as a fluctuant focus along the floor of the mouth and are usually painless. They may be purple in color.

ÛÛ CT easily defines the borders of the lesion in a cost- and

■■ Differential Diagnosis

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time-effective manner.

ÚÚ Other lesions mentioned in the differential can have a similar appearance.

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Case 66

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■■ Clinical Presentation A 42-year-old woman presents with an anterior neck mass.

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■■ Imaging Findings

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(A–C) There is diffuse enlargement of both the lobes of thyroid gland, right more than left. There is presence of multiple, irregular, low attenuating cystic areas (arrows) seen within both the lobes of the thyroid gland.

■■ Differential Diagnosis •• Multinodular goiter: Diffuse enlargement of both lobes of thyroid gland with well-defined margins. Presence of multiple cystic intraglandular nodules is seen. It has no clinical evidence for thyrotoxicity. •• Colloid cyst: A large cystic mass is seen within thyroid gland, generally unilateral with surrounding normal thyroid tissue. Sometimes, it may be hemorrhagic. •• Follicular adenoma: Enhancing unilateral solitary heterogeneous mass is seen within the thyroid gland.

■■ Essential Facts •• It is a mix of diffuse enlargement of thyroid gland and degenerative, colloid-filled, follicular nodules in the response to low levels of circulating endogenous thyroid hormone. Areas of hemorrhage, fibrosis, cyst formation, and calcification may be seen within the nodules. •• Most of these are not associated with high circulating levels of thyroid hormone and are not toxic. •• It is generally seen in elderly population with female predominance. •• The most common clinical presentation is a large anterior lower neck mass. Dyspnea, hoarseness, dysphagia, or superior vena cava (SVC) syndrome may also be present. •• Fine needle aspiration cytology may be performed in growing or hard nodules to rule out malignancy.

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•• Complete surgical removal is performed in cases of airway compression or profound dysphagia. No treatment is necessary for clinically asymptomatic patients.

■■ Other Imaging Findings •• On CT, there is enlargement of heterogeneously enhancing thyroid gland with well-defined margins and presence of multiple and nonenhancing low attenuating nodules, filled with colloid material. Areas of peripheral rimlike or amorphous calcification are commonly seen. Sometimes, mixed density areas of hemorrhage may be seen within the nodules. •• On MRI, a large heterogeneous T1 and T2 signal mass is seen due to presence of proteins, hemorrhage, and calcification. On coronal imaging, the brachiocephalic vessels are seen running along the inferior margin of the mass. •• On chest radiograph, tracheal deviation and/or superior mediastinal mass may be seen.

� Pearls & � Pitfalls ÛÛ When evaluating CT or MRI, always evaluate for mass

effect on trachea and esophagus and possible substernal extension.

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Case 67

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■■ Clinical Presentation An 11-year-old boy presents with facial swelling after recent illness.

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■■ Imaging Findings

A

(A) Contrast-enhanced axial CT image of the neck. There is a rim-enhancing fluid attenuation collection (arrow) between the left submandibular gland, sternocleidomastoid muscle, and carotid space structures.

■■ Differential Diagnosis •• Second branchial cleft cyst: Most common branchial cleft anomaly. May present as a fluid collection anywhere along the expected location of the cleft. •• Cystic hygroma: Could have a similar appearance but these lesions tend to be multilocular and multispatial. •• Necrotic lymph node: Whether due to neoplastic or inflammatory causes, a necrotic node could have similar appearance but would not likely be so homogeneous or have such a thin rim.

■■ Essential Facts •• Branchial apparatus refers to embryonic head and neck structures. Remnants of these structures can persist during postnatal life, resulting in cysts or sinus tracts. •• Remnants of the second branchial cleft are the most common branchial cleft anomalies and can occur anywhere

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along the expected location of the cleft, from the tonsillar fossa to the skin overlying the anterior inferior border of the sternocleidomastoid muscle. •• These lesions typically presents in late childhood or early adulthood after trauma or other inflammatory situations such as an upper respiratory infection. •• As noted, these remnants can occur as a cyst or even a sinus, extending to the skin surface. •• Surgical resection is curative. •• MRI or CT can demonstrate the lesion, which is of fluid attenuation and signal characteristics. Rim-enhancing wall is typically present.

� Pearls & � Pitfalls ÛÛ Second branchial cleft anomalies are the most common branchial cleft anomalies.

ÚÚ Treatment is surgical; therefore, the full extent of the lesion must be mapped out radiographically.

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Case 68

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■■ Clinical Presentation A 60-year-old man presents with hard left parotid mass.

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■■ Imaging Findings

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(A–C) A homogeneously enhancing irregular solid mass is seen at the superficial lobe of the left parotid gland (arrows) with irregular margins. There is likely pericapsular infiltration with thickening of the overlying left platysma (arrowheads).

■■ Differential Diagnosis

■■ Other Imaging Findings

•• Adenoid cystic carcinoma of parotid gland: Homogeneously enhancing, solid, irregular, parotid space mass is seen in an older man. •• Mucoepidermoid carcinoma of parotid gland: Well-defined or infiltrative carotid mass is more likely cystic than solid. Low T2 signal is seen on MRI. •• Benign mixed tumor of parotid gland: Well-defined homogeneously enhancing parotid space mass can mimic low-grade adenoid cystic carcinoma of parotid gland. •• Warthin tumor of parotid gland: Well-defined parotid mass enhances more heterogeneously.

•• On CT, a homogeneously enhancing parotid mass with ill-defined margins is seen in most cases. The margins may be smooth in cases of lower grade tumors. •• On MRI, low to intermediate T1 signal and moderately high T2 signal parotid mass exhibits homogeneous intense postcontrast enhancement. Possible perineural spread along the auriculotemporal nerve or cranial nerve VII is better evaluated on MRI.

� Pearls & � Pitfalls ÛÛ The goal of imaging is to evaluate the extent of mass,

■■ Essential Facts •• It is the second most common primary malignant mass originating from the peripheral parotid ducts of the parotid gland. •• It is generally seen in elderly population and is rare in first 2 decades of life. •• Most common presentation is a painful hard mass of the parotid gland with cranial nerve VII palsy. •• Perineural spread and distal metastasis to the lungs and bones is seen more frequently. •• Wide surgical resection with negative surgical margins followed by radiotherapy is the preferred treatment.

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perineural spread, and possible metastatic lymph nodes. However, metastatic spread to the lungs and bones is more common than to the lymph nodes. ÚÚ Carefully look for possible perineural spread along cranial nerve V also.

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Case 69

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■■ Clinical Presentation A 37-year-old man presents with a painful, swollen jaw.

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■■ Imaging Findings

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(A–C) Contrast-enhanced axial (A, soft tissue window) and coronal reformatted soft tissue (B) and bone (C) window CT images through the maxillofacial bones. There is a fluid collection along the lateral aspect of the mandible (arrows). An internal gas pocket is present (white circle). The collection is in continuity with a periapical lucency along the mandible (black circle).

■■ Differential Diagnosis •• Masticator space abscess: Most likely due to a gas-containing fluid collection in conjunction with likely periapical abscess. •• Masticator space hematoma: In the setting of immediate trauma, one could have a gas/fluid collection centered around the mandible. •• Rhabdomyosarcoma: Common neoplasm of the masticator space but would have some degree of enhancement and the clinical scenario would again be different.

■■ Essential Facts •• Abscesses are the most common focal lesions of the masticator space. Usually, they are secondary to adjacent dental disease, as in this case. •• Contrast-enhanced CT is the imaging modality of choice for examining the maxillofacial bones for complications of infections.

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•• CT imaging usually reveals a fluid collection, centered in the masticator space, adjacent to the mandible. Rim enhancement can be seen as well as gas produced from infectious organisms. •• Cross-sectional imaging will also detect any extramasticator space extension of the abscess or inflammatory process.

� Pearls & � Pitfalls ÛÛ Most common lesion of the masticator space. ÚÚ The masticator space extends superiorly along the

temporalis aponeurosis, travelling medial to the zygomatic arch and ending along the calvarium. This area must always be inspected for spread of disease.

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Case 70

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■■ Clinical Presentation A 57-year-old with history of left-sided cutaneous scalp angiosarcoma presents with swelling of the left parotid gland.

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■■ Imaging Findings

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(A, B) There is presence of a large peripherally enhancing low attenuating mass (arrow) in the anterior part of the superficial lobe of the left parotid gland. An additional heterogeneously enhancing smaller solid mass is also seen (arrow).

■■ Differential Diagnosis •• Nodal metastatic disease of parotid gland: Presence of a peripherally enhancing necrotic lesion is seen with an additional heterogeneously enhancing solid mass in the left parotid gland. The patient has history of aggressive skin malignancy of the scalp on the same side. •• Benign lymphoepithelial lesions of parotid gland: Mixed cystic and solid masses are seen in patient with HIVpositive status. Simultaneous tonsillar hyperplasia and cervical lymph node enlargement is generally seen. It is generally bilateral. •• Sjögren syndrome: Multiple bilateral small cystic lesions are seen with solid and cystic masses. It may be associated with collagen vascular disorder.

■■ Essential Facts •• Lymph nodes within the parotid gland are first-order lymph nodes draining the skull, external ear, and face. Metastatic secondary spread from squamous cell carcinoma and melanoma from this region results in nodal malignancy of the parotid gland. •• It is more commonly seen in the elderly male population. The incidence is greater in Sun Belt states like Arizona and California. •• Most common presentation is nonhealing ulcer on the skin of face, scalp, or auricle with enlarging parotid mass. Facial pain and palsy of cranial nerve VII may also be present. Presence of nodal metastatic disease of the parotid gland is a poor prognostic indicator.

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•• Total parotidectomy and neck dissection followed by radiotherapy with or without chemotherapy is the preferred treatment.

■■ Other Imaging Findings •• On CT, solitary or multiple, round or ovoid, solid or necrotic unilateral masses are seen with moderate enhancement of solid component. Simultaneous presence of periauricular or cervical nodal metastasis may be seen. •• On MRI, single or multiple, round or ovoid, solid or necrotic, low to intermediate T1, and intermediate to high T2 signal unilateral masses with heterogeneous contrast enhancement are seen. •• Presence of perineural spread along cranial nerve VII or cervical nodal metastasis should be evaluated on MRI. •• FDG-PET is more sensitive to differentiate nodal malignancy of smaller lymph nodes.

� Pearls & � Pitfalls ÛÛ FDG-PET may be performed in all patients with ag-

gressive squamous cell carcinoma or melanoma of face, scalp, and external ears. If positive, further evaluation with MRI may be performed for local staging and for evaluating possible perineural spread. ÚÚ Unilateral nodal disease suggests first-order metastasis from adjacent scalp or skin sites, whereas bilateral multifocal disease signifies hematogenous metastatic spread or systemic disease.

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Case 71

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■■ Clinical Presentation A 17-year-old girl presents with visual abnormalities.

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■■ Imaging Findings

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(A–D) Coronal T2 (A, B) and T1 postcontrast (C, D) images demonstrate substantially enlarged T2 hyperintense, enhancing optic nerves (white arrows) with signal alterations also extending into the chiasm (black arrow). Additionally, there is a focus of T2 prolongation within the left basal ganglia (arrowhead).

■■ Differential Diagnosis •• Optic nerve glioma (ONG): This is the most likely diagnosis given the optic nerve findings, particularly the substantial enlargement of the chiasm. The additional basal ganglia “bright spot” (neurofibromatosis type 1 [NF1]) supports the finding. •• Optic neuritis: Would not see such substantial enlargement of the chiasm; also, would not have additional basal ganglia findings but may have white matter changes (multiple sclerosis). •• Lymphoma: Could potentially have this appearance, as lymphoma is a great mimicker of disease.

■■ Essential Facts •• ONGs are frequently low grade (I/IV) astrocytomas of the optic pathway found in children. Rare, high-grade ONGs are found in adults. •• Lesions can involve any portion of the nerve from the orbit to the optic tract; it can be bilateral. •• May be seen in isolation or as a manifestation of NF1 (. 25%).

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•• MRI is the imaging modality of choice. Lesions can have a variety of appearances, with varying degrees of tissue enlargement, enhancement, and T2 prolongation. •• Some tumors may appear as a perineural growth on MRI, mimicking a meningioma or other extra-axial process.

■■ Other Imaging Findings •• CT can aid in the diagnosis but is less useful in assessing intracranial extent.

� Pearls & � Pitfalls ÛÛ Associated with NF1. Therefore, search for other signs

such as T2 “bright spots” within the deep gray nuclei and cerebellum. ÚÚ Follow the entire expected course of the nerves from the orbit to the visual pathways to assess for full extent of the lesion.

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Case 72

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■■ Clinical Presentation A 32-year-old presents with left neck mass.

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■■ Imaging Findings

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(A, B) A homogeneously enhancing submucosal mass is seen on the left side of the tongue base (black arrow), extending up to midline. There is presence of an enlarged, ovoid, left level 2 lymph node with pericapsular spread with infiltration and thickening of the overlying left platysma muscle (white arrows).

■■ Differential Diagnosis •• Minor salivary gland carcinoma of the tongue: A homogeneously enhancing, infiltrating, submucosal mass is seen at the tongue base with metastatic nodal disease. •• Squamous cell carcinoma of tongue: Arises from mucosal surface with poorly circumscribed margins. Postcontrast enhancement is moderate. It may be associated with lymph node enlargement. •• Benign mixed femur of minor salivary gland: Sharply marginated, homogeneously enhancing, benign mass is seen without associated lymphadenopathy.

■■ Essential Facts •• It is a rare, aggressive, infiltrating, malignant neoplasm of the mucosal surface of the pharynx. It arises from the ducts and acini of minor salivary glands and could be adenoid cystic carcinoma, adenocarcinoma, or mucoepidermoid carcinoma. •• Most common location is the junction of the hard and soft palate, sinonasal region, tongue, faucial tonsils, adenoids, or lingual tonsils. •• Most common presentation is painless, slowly growing, submucosal mass in the pharyngeal wall. Presence of facial numbness and paresthesia likely represents perineural spread along cranial nerve V1 or V2. •• Generally is seen in adult to elderly population.

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•• Wide surgical resection of the mass and perineural spread with postoperative radiotherapy is preferred for treatment.

■■ Other Imaging Findings •• On contrast-enhanced CT, a homogeneously enhancing, locally aggressive submucosal mass is seen. There may be erosion of underlying bony structures and widening of neural foramina due to early perineural spread. •• On MRI, it exhibits isointense T1 signal and hyperintense T2 signal. Infiltration of surrounding structures including bone marrow and perineural spread is well visualized on T1-weighted imaging due to inherent contrast against high T1 signal fat. Intense homogeneous postcontrast enhancement is best evaluated on fat-saturated postcontrast T1-weighted sequences.

� Pearls & � Pitfalls ÛÛ MRI is the preferred imaging modality due to inherent

tissue contrast and ability to detect early perineural spread. The checklist for perineural spread includes pterygopalatine fossa, greater palatine foramen, foramen rotundum, and Meckel’s cave. ÚÚ Late recurrence is common. Follow-up by imaging must be performed up to 10 years posttreatment.

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Case 73

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■■ Clinical Presentation A 12-year-old boy presents with a head lump.

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■■ Imaging Findings

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(A) Bone window axial CT image through the head reveals a lytic lesion of the calvarium (circle). (B, C) Pre- and postcontrast sagittal T1-weighted images through that region demonstrate a low T1 signal intensity lesion with robust contrast enhancement (arrows).

■■ Differential Diagnosis •• Eosinophilic granuloma (EG): In a child or young adult, these lesions are relatively common, presenting as lytic foci involving one or more bones, particularly the calvarium, ribs, and vertebrae. •• Metastasis: Another top differential. Metastatic foci from a variety of tumors can present as lytic bone lesions. •• Primary bone tumor: Unusual location/appearance for a primary bone tumor, such as an osteogenic sarcoma variant, given the patient’s age.

•• Radiographically, lesions present as lytic foci in one or more bones, with or without an associated soft tissue component. •• MRI is nonspecific, as it demonstrates an enhancing focus within the involved structure.

■■ Other Imaging Findings •• EG can have a variety of appearances on bone scan, with increased or decreased activity.

■■ Essential Facts

� Pearls & � Pitfalls

•• EG is a nonneoplastic process representing one of three forms of Langerhans cell histiocytosis, with replacement of normal tissue by a histiocytic cell population. •• Usually seen in the pediatric or young adult population. Patients can present with localized pain, swelling, leukocytosis, or may be asymptomatic. Lung involvement is occasionally seen. •• Most cases regress spontaneously within a few years, and thus conservative treatment is generally the rule.

ÛÛ Relatively common osseous lesion of child and young

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adulthood.

ÛÛ Calvarial involvement is quite common, representing the most often involved osseous structure.

ÚÚ Imaging findings are nonspecific, as many other benign as well as malignant processes can have a similar appearance.

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Case 74

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■■ Clinical Presentation A 24-year-old presents with a pulsatile right neck mass.

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■■ Imaging Findings

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■■ Differential Diagnosis •• Carotid body paraganglioma: Intensely enhancing, high T2 signal mass with multiple flow voids and salt-andpepper appearance on T1-weighted imaging is seen at the level of carotid bifurcation, splaying the ECA and ICA. A highly vascular intensely enhancing mass is seen on contrast-enhanced CT. •• Glomus vagale paraganglioma: The mass is seen at higher level within the carotid space, with relation to ICA, just below the posterior skull base. The imaging characteristics are similar to carotid body paraganglioma. •• Carotid space schwannoma: A well-defined soft tissue mass is seen in the carotid space without splaying of ICA and ECA. There is lack of high velocity serpentine flow voids and absence of tumor blush.

■■ Essential Facts •• It is a benign, vascular tumor originating from carotid glomus bodies or paraganglia, which are composed of chemoreceptor cells at the carotid bifurcation. Although the carotid body paraganglia is the most common location for paraganglioma, it can also be found within the temporal bone, jugular foramen, and upper carotid space. •• Most of the paraganglioma are sporadic; however, a variable percentage also belong to familial type. •• May be associated with von Hippel-Lindau syndrome, MEN type II syndrome, or adrenal pheochromocytoma. •• Most common clinical presentation is a slow-growing, painless but pulsatile vascular neck mass. There may be paresis of cranial nerves X and XII. •• Most common presentation is in fourth and fifth decade with male dominance.

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C

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(A) Contrast-enhanced CT exhibits a well-defined, intensely enhancing, vascular mass at the right carotid bifurcation (arrow), splaying the external carotid artery (ECA) and internal carotid artery (ICA). (B) T1-weighted axial imaging displays a heterogeneous mildly high T1 signal (arrow) well-defined mass at the level of carotid bifurcation. (C) On T2-weighted image, the mass appears hyperintense (arrow) with presence of serpiginous flow voids apparent. (D, E) Postcontrast axial and coronal imaging exhibits a well-defined, intensely enhancing mass at the carotid bifurcation, splaying the ECA and ICA (arrow).

•• Smaller lesions can be followed with imaging surveillance. Surgical excision is the preferred treatment with preoperative embolization to control operative bleeding. Radiotherapy is utilized for nonsurgical candidates.

■■ Other Imaging Findings •• On contrast-enhanced CT, an intensely enhancing mass is seen at the level of carotid bifurcation, splaying the ECA and ICA and displacing the ICA posterolaterally. •• On T1-weighted MRI, atypical “salt and pepper” appearance may be seen. Low T1 signal punctate or curvilinear “pepper” is mixed in high T1 signal “salt” of tumor parenchyma. The low T1 signal, curvilinear, high velocity flow voids from feeding arteries are contrasted against high T1 signal foci of the parenchymal subacute hemorrhage. •• MRA of neck exhibits typical splaying of ECA and ICA. •• On angiography, multiple serpentine feeding arteries are visualized, most likely originating from ascending pharyngeal artery. An intense vascular blush and early draining veins are seen.

� Pearls & � Pitfalls ÛÛ In familial case group, genetic screening of family

members and imaging surveillance with MRI starting in early adulthood is recommended. Look for multicentric lesions at the level of the high carotid space, contralateral carotid bulb, jugular foramen, and middle ear cavity of temporal bone.

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Case 75

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■■ Clinical Presentation An 18-year-old man presents with diabetes insipidus.

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■■ Imaging Findings

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(A, B) Sagittal and coronal T1-weighted postcontrast images were obtained. There are enhancing lesions located both within the sella turcica (arrow) as well as within the pineal region (arrowhead). Enhancing soft tissue is also noted along the septum pellucidum (circle).

■■ Differential Diagnosis •• Germ cell tumor (GCT): A good choice due to involvement of both the pineal bed and the sellar regions in a young male patient. •• Metastasis: Multiple focal areas of intracranial enhancement raise the possibility of metastatic disease. •• Quadrilateral retinoblastoma: Could be seen with infant/ young child involvement of retinoblastoma, including bilateral orbits, sellar/suprasellar, and the pineal regions.

•• On imaging, lesions have variable appearances due to different possible cell line involvement. Pure germinomas may be rather homogeneously hyperintense on CT. •• Calcification can be seen with GCTs but can also be seen with other pineal or suprasellar region tumors. •• All lesions tend to enhance on CT and MR. Fat density or signal intensity can be seen with teratomatous involvement.

� Pearls & � Pitfalls ÛÛ Intracranial GCTs can have a variety of appearances due

■■ Essential Facts •• Tumors derived from germ cells include seminomas/germinomas as well as other cell lines such as choriocarcinomas and yolk sac tumors. •• Intracranial involvement can be primary or secondary. Both forms are usually seen in childhood and young adult patient populations. •• Patients can present with a variety of symptoms, including diabetes insipidus or hormonal abnormalities due to sellar involvement, hydrocephalus from pineal involvement, or Parinaud syndrome due to compression of the quadrigeminal plate.

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to the involvement of various cell lines.

ÛÛ Pineal lesions are typically tumors of pineal origin or GCTs but can also include astrocytomas and meningiomas.

ÚÚ Pineal calcification does not occur in children under

10 years of age. If present on CT in such patients, a thorough evaluation for tumors in this region must occur. ÚÚ Central diabetes insipidus may be the first sign of a subtle pineal/sellar tumor. Even if the initial radiographic evaluation is normal, repeat imaging at a later date is usually warranted.

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Case 76

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■■ Clinical Presentation A 42-year-old woman presents with otalgia.

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■■ Imaging Findings

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(A) T1-weighted axial imaging reveals and oral rounded mass at left carotid space with anterior displacement of left carotid artery (black arrow). A similar smaller mass is also seen on the right side. (B) T2-weighted axial imaging shows previous hyperintense T2 signal of this mass (black arrow). (C) Postcontrast T1-weighted imaging reveals homogeneous contrast enhancement (black arrow). (D) Postcontrast fat-saturated T1-weighted imaging reveals marked intense postcontrast enhancement (arrow). The right-sided mass is now more conspicuous.

■■ Differential Diagnosis

■■ Other Imaging Findings

•• Vagal schwannoma of carotid space: Rounded, smooth, well-defined, carotid space mass with anterior displacement of carotid artery. There is homogeneous and intense postcontrast enhancement with lack of serpentine high velocity flow void areas. •• Glomus vagale paraganglioma: Rounded, well-defined, hyperintense T2 signal, carotid space mass is seen with intense homogeneous postcontrast enhancement. There is presence of serpentine high velocity flow void areas. •• Reactive lymph nodes: Commonly seen in younger patients. Multiple enhancing ovoid lesions are seen at carotid spaces and retropharyngeal spaces with moderately high T2 signal and moderate postcontrast enhancement.

•• On contrast-enhanced CT, a well-defined rounded mass in carotid space of the neck is seen with intense postcontrast enhancement. In the suprahyoid neck, the mass displaces the parapharyngeal space anteriorly and the posterior belly of digastric muscle laterally. In the infrahyoid neck, the mass displaces the thyroid cartilage and trachea to the contralateral side. The carotid artery is seen at the anteromedial surface of the mass with varying degree of displacement. •• On MRI, the tumor exhibits low T1 and high T2 signal, like any schwannoma with intense homogeneous postcontrast enhancement. Areas of central cyst formation may be seen in larger masses. In coronal and sagittal planes, the mass reveals a fusiform shape along the length of carotid artery. •• There is lack of high velocity serpentine flow void areas within the tumor, differentiating it from a paraganglioma. •• On angiography, a moderately vascular mass is seen with tortuous but nonenlarged feeding vessels. Presence of scattered “puddles” of contrast is characteristic.

■■ Essential Facts •• A smooth, well-marginated, benign tumor is seen originating from Schwann cells surrounding the vagus nerve in the carotid space of the neck. •• It is most commonly discovered between third and fifth decade of life and does not show any sex predilection. •• It is a slow-growing mass that may be clinically silent. Mass effect on surrounding structures can lead to airway compromise or asymmetric swelling of the neck. Otalgia, vertigo, hoarseness of voice, pressure in the ears, and Horner syndrome may be present. •• Total surgical removal is preferred treatment.

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� Pearls & � Pitfalls ÛÛ Lack of high velocity serpentine flow voids differentiates it from glomus vagale paraganglioma.

ÚÚ It cannot be differentiated from vagal neurofibroma by CT or MR imaging.

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Case 77

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■■ Clinical Presentation A 14-year-old girl presents with right-sided sensorineural hearing loss.

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■■ Imaging Findings

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(A–D) Noncontrast high-resolution temporal bone axial CT imaging was performed on the right side (A, B) and the left side (C, D). There is mineralization of the basal turn of the right cochlea (arrow). The right superior semicircular canal is also mineralized and poorly seen (black circle). The left superior semicircular canal is normal in appearance (arrowheads), as is the left cochlea (curved arrow).

■■ Differential Diagnosis •• Labyrinthitis ossificans (LO): Classic appearance of cochlear and vestibular apparatus mineralization. •• Otospongiosis: Can alter and cause either sclerosis or spongiotic changes along the otic capsule rather than within the structures themselves. •• Paget’s disease: Can appear similar to otospongiosis but tends to involve the pericapsular structures.

■■ Essential Facts •• LO is an idiopathic condition resulting in first fibrotic and then ossific changes of the cochlear and vestibular structures. •• It is typically seen in the setting of prior meningitis but can also be due to prior trauma.

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•• Patients present with sensorineural hearing loss. •• In the first fibrous phase, CT findings may be minimal. High-resolution T2-weighted images may show loss of the normal fluid high signal intensity within the affected structures. •• In later stages, CT findings are more demonstrative of the ossification of this process.

� Pearls & � Pitfalls ÛÛ Major association with prior meningitis. ÚÚ Initial fibrous stage is often better seen on MRI than on CT.

ÚÚ Evaluation of the degree of ossification (as well as the course of the facial nerve) is important if cochlear implantation is being considered.

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Case 78

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■■ Clinical Presentation A 21-year-old woman presents with large, asymmetric, left-sided neck swelling.

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■■ Imaging Findings

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(A, B) Irregular nonenhancing hypodense nodules are seen within the left lobe of the thyroid gland with irregular lateral margins (white arrow). There is presence of large cystic left level 3 and level 4 lymph nodes (white arrow) with smaller lymph nodes with ring and nodular contrast enhancement seen superiorly (small white arrow). There is mass effect on the trachea with contralateral displacement. There is medial displacement of left internal carotid artery (black arrow).

■■ Differential Diagnosis

■■ Other Imaging Findings

•• Differentiated thyroid carcinoma: Focal, unilateral, irregular left thyroid lobe nodule with irregular lateral margins, large left carotid space, and cystic level 3 and level 4 lymph nodes. •• Follicular adenoma a thyroid gland: Solitary, low attenuating, unilateral thyroid gland mass without pericapsular spread or lymph node enlargement. •• Hemorrhagic colloid cyst: A large, unilateral cystic mass is seen within thyroid gland with surrounding normal thyroid tissue. No evidence for pericapsular spread or lymph node enlargement is seen.

•• On CT, there is a unilateral, focal, irregular low attenuating mass within the thyroid gland. There may be evidence for extracapsular invasion. Areas of calcification and hemorrhage may be seen. Presence of local regional lymph node metastasis is common. The primary thyroid lesion may appear similar to a benign adenoma. The lymph nodal metastasis may be cystic, solid, or mixed. Areas of calcification and nodular enhancement are seen. •• On MRI, a heterogeneous, hyperintense T2 signal mass with heterogeneous postcontrast enhancement is seen. The invasive margins are irregular. The lymph nodes may exhibit high T2 signal due to necrotic changes and nodular postcontrast enhancement. Areas of high T1 signal likely represent hemorrhage or colloid material. •• On ultrasound, a hypoechoic to isoechoic heterogeneous solid mass is seen with or without calcification. •• On technetium 99m pertechnetate, a cold nodule likely represents malignancy. •• I-131 is utilized to perform whole-body imaging following surgical resection of the thyroid gland to detect metastatic deposits.

■■ Essential Facts •• All the malignant neoplasms of the thyroid gland with a well-defined histology are called differentiated thyroid carcinoma. It mainly includes papillary (90%) and follicular types. •• It is the most common malignant endocrine neoplasm and accounts for 1% of all the malignant neoplasm of the human body. About 80% of all the thyroid malignancy is differentiated carcinoma. It may be sporadic or radiation induced. •• The most common clinical presentation is an anterior paramedian lower cervical neck mass. At the time of presentation, lymph node enlargement is often larger than the tumor. •• Total thyroidectomy and neck dissection with removal of lymph nodes is the preferred treatment.

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� Pearls & � Pitfalls ÛÛ Follicular adenoma can mimic early differentiated

thyroid carcinoma without lymph node metastasis on every imaging modality. ÚÚ Well-defined borders or the presence of calcification or cysts within a thyroid mass do not rule out malignant etiology.

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Case 79

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■■ Clinical Presentation A 16-year-old girl presents with headache.

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■■ Imaging Findings

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(A–C) Noncontrast axial bone paranasal sinus CT (A) and coronal reformatted images in bone (B) and soft tissue windows (C). There is opacification and expansion of the left ethmoid and sphenoid sinuses (asterisks) with high attenuation material (arrow). Note relative preservation of the internal ethmoid septae (arrowhead).

■■ Differential Diagnosis •• Allergic fungal sinusitis: High on the differential list due to radiographic findings of sinus expansion (rather than erosion) by high attenuation material. •• Inspissated secretions: Can appear as high attenuation within the sinuses. However, sinuses are not usually filled and expanded with such material. •• Paranasal sinus blood: Unusual, unless in the setting of trauma.

■■ Essential Facts •• Allergic fungal sinusitis represents an immune response to ubiquitous fungal species. •• Patients can be asymptomatic or present with typical rhinitis or sinusitis symptoms or cosmetic deformity (sinus expansion) or rarely intracranial extension. •• Affected patients tend to be atopic in contrast to patients with invasive fungal infections who tend to be immunocompromised or immunosuppressed.

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•• Mucin is produced by the fungus, resulting in the typical high attenuation material noted on CT. Expansion of the sinus results from mucin accumulation. •• Treatment is a combination of surgical removal and immunomodulation.

■■ Other Imaging Findings •• MRI often underestimates or misses disease, as fungal products may show signal variability and/or dropout.

� Pearls & � Pitfalls ÛÛ High attenuation expansion of the sinuses on CT suggests this diagnosis, which is often underappreciated clinically.

ÚÚ Fungus may not be well seen on MRI due to signal variability and dropout.

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Case 80

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■■ Clinical Presentation A 30-year-old man presents with dysphagia and neck pain.

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■■ Differential Diagnosis •• Tornwaldt’s cyst: A rounded, benign high T1 and T2 signal posterior nasopharyngeal mass with enhancement of the anterior surface covered by nasopharyngeal mucosa. •• Adenoidal hyperplasia: Diffuse adenoidal hyperplasia is generally not rounded in midline and exhibits low attenuation and low T2 signal. On postcontrast imaging, transverse septa traversing the hyperplastic tissue are seen. •• Cephalocele: A rare midline sphenoidal cephalocele may project inferiorly into the nasopharynx. However, a sinus tract connecting the cephalocele to cranial cavity can be seen.

■■ Essential Facts •• It is the most common congenital lesion of the nasopharynx. It is a benign, midline, nasopharyngeal, developmental cyst covered with mucosa anteriorly and has longus coli muscles posterolaterally. •• More commonly seen in middle-aged to elderly population, it is a common incidental finding in ∼5% of MRI studies.

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(A) T1 sagittal image exhibits a lobulated mildly high T1 signal mass at the posterior mucosal surface of the nasopharynx (arrow). (B) FLAIR-weighted axial imaging exhibits mildly high signal (arrow), compatible with proteinaceous content. (C) T2 axial imaging exhibits a hyperintense T2 signal rounded mass (arrow). (D) Postcontrast T1 axial imaging exhibits enhancement (arrow) of mucosal deflection along the anterior surface of this mass.

•• If infected, it can become larger and result in unpleasant taste and bad breath. Intermittent nasopharyngeal discharge, constant nasal speech, sore throat, and eustachian tube dysfunction are other less common complications. •• If chronically infected and painful, complete surgical excision or marsupialization surgery is performed.

■■ Other Imaging Findings •• On CT, hypo- to intermediate density rounded mass without contrast enhancement is seen. Only edema enhancement is seen on postcontrast imaging. •• On MRI, high T1 and T2 signal a rounded lesion in midline posterior nasopharyngeal mucosal space is diagnostic. On postcontrast imaging, only a thin rim enhancement of overlying mucosa is seen.

� Pearls & � Pitfalls ÛÛ If infected, it can present with occipital headache, halitosis, and nasopharyngeal discharge.

ÚÚ When small, it can be indistinguishable from normal lymphoid tissue.

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Case 81

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■■ Clinical Presentation A 6-month-old infant presents with unilateral facial swelling and discoloration.

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(A–C) Multiplanar MRI with and without contrast enhancement, including axial T2, T1 pre-, and postcontrast images. There is extensive replacement of the left parotid gland with T2 hyperintense, enhancing tissue (arrows). Note the normal appearing right parotid gland (arrowheads).

■■ Differential Diagnosis •• Infantile hemangioma: Common location for these lesions in the infant population. Correlation with physical exam findings is key. •• Cystic hygroma: Although venolymphatic malformations can occur anywhere, this lesion does not have the cysts usually associated with such lesions. •• Arteriovenous malformation: Although this lesion may have one or two flow voids, the majority of the mass has a rather homogeneous appearance.

•• Head and neck lesions may affect the orbit, airway, or other vital areas and thus may require intervention. •• Can be associated with PHACE syndrome (posterior fossa malformations, hemangiomas, arterial abnormalities, aortic coarctation, and eye anomalies) as well as with intracranial vascular malformations. •• On MRI, lesions are rather homogeneous with T2 prolongation and enhancement. Some prominent flow voids may be present. •• Dynamic contrast-enhanced CT demonstrates rapid homogeneous enhancement of the lesion.

■■ Essential Facts

� Pearls & � Pitfalls

•• Infantile hemangiomas are common, benign neoplasms of infancy, the majority of which are clinically apparent by 6 months of age. •• They can be found anywhere along the body, including the head and neck region. Deep tissue lesions may be difficult to detect clinically. •• Most lesions spontaneously regress, over months to years. Steroid and laser treatment can also be used to facilitate regression.

ÛÛ Most common benign vascular neoplasm in infants. ÚÚ Other entities, both benign and malignant, may have a

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similar appearance radiographically, and thus correlation with clinical information and physical exam findings is essential.

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Case 82

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■■ Clinical Presentation A 62-year-old presents with chronic sore throat.

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■■ Imaging Findings

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(A, B) A moderately enhancing soft tissue mass is seen at the postcricoid region (white arrow) with sparing of the cricoid cartilage. (C–F) A low T1 (black arrow) and high T2 signal mass (white arrow) with heterogeneous postcontrast enhancement is seen at the postcricoid region. On sagittal T1-weighted imaging, the extensive vertical extent of the mass along the posterior pharyngeal wall (white arrow) is seen.

■■ Differential Diagnosis •• Squamous cell carcinoma of hypopharynx: A moderately enhancing postcricoid mass on CT exhibits low T1 and high T2 signal on MRI with heterogeneous postcontrast enhancement; positive history of smoking and drinking. •• Adenoid cystic carcinoma of minor salivary gland: The imaging characteristics are similar to squamous cell carcinoma, but the incidence is less. •• Cervical esophageal carcinoma: Presents with dysphagia and weight loss rather than sore throat. It can involve the postcricoid hypopharynx, larynx, or thyroid gland but does not extend superiorly along the posterior hypopharyngeal wall.

■■ Essential Facts •• Hypopharynx is rich in vascular and lymphatic structures, located between the floor of oropharynx and cervical esophagus. It consists of the piriform sinuses, the posterior pharyngeal wall, and the postcricoid region. •• The squamous cell carcinoma in the region of epiglottis, aryepiglottic folds (excluding posterior walls), and false vocal cords, which are part of supraglottic larynx, is less aggressive and should not be confused with hypopharyngeal mass. •• It is more commonly seen in elderly males with a history of smoking and drinking.

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•• The most common clinical presentation is chronic sore throat with dysphagia and possible cervical pain. •• Surgical resection followed by radiation is the preferred treatment. Larger masses require laryngopharyngectomy.

■■ Other Imaging Findings •• On CT scan, a moderately enhancing, locally invasive mass can be seen. Depending on location, invasion of thyroid or cricoid cartilage should be evaluated. Extension to carotid space, prevertebral space, retropharyngeal space, glottic space, or cervical soft tissue is possible. •• On MRI, an intermediate to low T1 signal and high T2 signal mass with irregular and heterogeneous postcontrast enhancement is seen. •• Due to low breathing and swallowing artifacts, contrastenhanced CT is the preferred technique. •• Due to multiplanar imaging, MRI better demonstrates the craniocaudal extent of the disease.

� Pearls & � Pitfalls ÛÛ It is good to know the details of endoscopic study be-

fore imaging, so that one can more accurately evaluate deeper structures. ÚÚ Artifacts from breathing, coughing, and swallowing are a challenge for CT and MR imaging. On CT, coronal and sagittal reconstructions are helpful to evaluate vertical extent.

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Case 83

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■■ Clinical Presentation A 2-year-old boy presents with fever and drooling.

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■■ Differential Diagnosis •• Tonsillar/peritonsillar abscess: A large rim-enhancing tonsillar fluid collection in a sick child is most likely a tonsillar abscess. •• Suppurative lymph node: Smaller (1 cm) fluid collection in this location may simply represent a liquefied, infected lymph node. •• Cystic hygroma: If the patient developed an enlarging focus along the pharynx after a recent upper respiratory infection (URI), one may consider this diagnosis.

■■ Essential Facts •• Acute tonsillar/peritonsillar abscess is usually encountered in the setting of pharyngitis. •• Patients present with pharyngeal pain, pain upon swallowing, fever, and physical exam signs of tonsillar enlargement. •• Most commonly seen in the pediatric and young adult population. Treatment is typically performed with needle aspiration, complemented by medical antibiotic therapy. However, excision and drainage or tonsillectomy may be necessary in some cases. •• CT is the method of choice in diagnosis due to speed and ease of the exam process.

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(A) Contrast-enhanced axial CT image was obtained through the neck. There is a rim-enhancing fluid collection (arrow) within the right tonsil/ peritonsillar space. The airway is deviated to the left.

•• Low attenuation, rim-enhancing fluid collection is the hallmark of drainable abscess formation. Mixed attenuation findings without a discrete fluid collection in this region suggest either phlegmon or early abscess, which may be managed medically. •• Tiny (∼1 cm) collection suggests the presence of a suppurative lymph node, which also may be treated medically.

■■ Other Imaging Findings •• MRI shows similar findings but is not typically performed in such patients due to time constraints and motion (swallowing/breathing) or air interface artifacts.

� Pearls & � Pitfalls ÛÛ Common condition; rim-enhancing substantial fluid

collection in a toxic patient will most likely represent this entity. ÚÚ Tiny collection suggests a suppurative node that may be treated medically.

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Case 84

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■■ Clinical Presentation A 30-year-old presents with right mandibular pain and difficulty in swallowing following periodontal treatment for a decaying tooth.

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■■ Differential Diagnosis •• Sublingual space abscess: An irregular and tubular cystic mass with peripheral rim enhancement is seen, lying superomedial to the mylohyoid sling in the sublingual space, in a patient with a history of dental infection with sudden onset sublingual pain and dysphagia. Bone window reveals cortical dehiscence at the site of tooth removal. •• Simple ranula: An irregular and tubular cystic mass in sublingual space is seen with thin nonenhancing wall. No evidence for surrounding cellulitis or edema. •• Epidermoid cyst of sublingual space: Rounded or tubular cystic mass in sublingual space can be seen with thin nonenhancing wall. No evidence for cellulitis or edema. It can look similar to a simple ranula. •• Ludwig angina: Presence of cellulitis and edema is seen in sublingual space, submandibular space, and/or tongue without evidence of a focal cystic abscess.

■■ Essential Facts •• It is most often secondary to dental decay of lower molar or premolar tooth. Rupture of periodontal or root canal abscess with or without iatrogenic intervention introduces staphylococci or bacteroids superior to the mylohyoid line, resulting in a sublingual space abscess. •• Submandibular sialadenitis is more likely secondary to surrounding cellulitis. The incidence of submandibular sialolithiasis as the primary cause is very low. •• It is a part of the spectrum of Ludwig angina, which can be present with cellulitis even without frank abscess formation. •• It is seen more often in the elderly population and immunocompromised patients but can be seen in pediatric age group and healthy adults.

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(A–D) An irregular peripherally ring-enhancing mass in the sublingual space (arrow) superomedial to mylohyoid sling (arrow), draining up to midline. (E) Bone window reveals cortical dehiscence (arrow) at the site of tooth removal.

•• The most common clinical presentation is painful sublingual swelling and dysphagia with or without fever. •• Surgical evacuation of abscess cavity, removal of infected tooth, and intravenous antibiotics can result in full recovery.

■■ Other Imaging Findings •• On contrast-enhanced CT, an irregular, rounded, or tubular cystic mass with peripheral rim enhancement is seen. There may be extensive edema and soft tissue stranding of sublingual space, floor of mouth, and tongue. Lymph node enlargements at level 1 and 2 are common. •• Bone windows may reveal cortical dehiscence, periodontal/ root abscess, or mandibular osteomyelitis. •• On MRI, a high T2 and low T1 signal cystic mass with peripheral rim enhancement is seen. Superomedial location to mylohyoid muscle is better appreciated on fat-saturated postcontrast T1-weighted coronal imaging. High T2 signal within the bone marrow of mandible signifies osteomyelitis. When bilateral, a typical horseshoe-shaped abscess overlying the mylohyoid sling is seen in coronal imaging.

� Pearls & � Pitfalls ÛÛ Contrast-enhanced CT scan with soft tissue and bone

windows can give most answers for a sublingual space abscess. ÚÚ Beam hardening artifacts from dental amalgam sometimes limit evaluation of the mandibular ramus and sublingual space. Presence of possible submandibular sialolithiasis as primary cause may be missed on MRI; however, the incidence is low.

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Case 85

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■■ Clinical Presentation A 28-year-old man presents with head pain.

■■ Further Work-up An additional exam was performed.

C

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■■ Imaging Findings

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(A, B) Contrast-enhanced skull base axial CT images in soft tissue and bone windows demonstrate an enhancing soft tissue focus that extends from the left aspect of the nasopharynx into the clivus and left carotid space with osseous destruction (circles). (C, D) Diffusion-weighted MRI (C) with corresponding ADC map (D) suggest that this soft tissue impedes diffusion (arrows).

•• Constitutional symptoms may also be apparent, including weight loss, night sweats, fever, and decreased energy. •• On imaging, extranodal lymphomas are protean in appearance. T2 shortening and restricted diffusion may suggest the diagnosis, likely due to relatively increased cellularity of the tumors.

•• Lymphoma: Lymphoma can occur in essentially every region of the body. Restricted diffusion is often noted, likely due to increased cellularity. •• Nasopharyngeal carcinoma: Excellent location for this disease entity; less likely to restrict diffusion. •• Metastasis: As in lymphoma, can occur in any region of the body; again, less likely to restrict diffusion.

■■ Other Imaging Findings

■■ Essential Facts

•• FDG-PET has been used to monitor response to therapy in NHL patients.

•• Lymphomas are generally divided into Hodgkin disease (HD) and non-Hodgkin lymphoma (NHL) types based on the presence (HD) or absence (NHL) of Reed-Sternberg cells. •• NHL types are more likely to arise within extranodal sites in comparison to HD patient. •• NHL types are more commonly seen in older individuals (. 50 years old) and can present with a variety of symptoms depending on the organ/areas involved. •• Extranodal head and neck NHL types may present with symptoms related to the organ involved, such as head pain and cranial nerve palsies in a patient with skull base involvement.

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� Pearls & � Pitfalls ÛÛ Restricted diffusion of an aggressive mass may suggest the diagnosis of NHL.

ÚÚ Full body imaging must be performed in such patients to ensure proper disease staging.

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Case 86

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■■ Clinical Presentation A 10-month-old infant presents with swelling of left cheek.

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(A) Well-defined but irregular left parotid mass is isointense to muscle on T1-weighted images (black arrow). (B) On T2-weighted imaging, the mass appears hyperintense to muscles (black arrow). However, the subcutaneous fat exhibits higher T2 signal than the mass. Serpiginous flow void areas are seen adjacent to and within the mass (black arrow). (C) On fat-saturated T1-weighted postcontrast imaging, intense postcontrast enhancement of the mass is seen. (D) On T2-weighted imaging, the mass appears hyperintense to muscles (arrow). However, the subcutaneous fat exhibits higher T2 signal than the mass. Serpiginous flow void areas are seen adjacent to and within the mass.

■■ Differential Diagnosis

■■ Other Imaging Findings

•• Infantile hemangioma of parotid gland: A well-defined mass of infancy exhibits diffuse postcontrast enhancement and presence of prominent vessels within and adjacent to the mass. •• Congenital hemangioma: It is present at birth or on prenatal imaging and rapidly involutes by beginning of childhood. •• Venous malformation: There is presence of large venous lakes with low T1 and high T2 signal, diffuse postcontrast enhancement, and presence of phleboliths. •• Plexiform neurofibroma: It is generally associated with additional stigmata of NF1 like café au lait skin lesions. Infiltrative mass with irregular margins that crosses multiple spaces of the neck.

•• On noncontrast CT, it appears hypo- to isodense mass without evidence for calcification. There is no evidence for osseous erosion; however, bony remodeling is possible. •• On contrast-enhanced CT, diffuse, avid postcontrast enhancement is seen with presence of prominent vessels in the vicinity of and within the mass. •• On MRI, iso-T1 signal mass appears mildly hyperintense to muscles on T2-weighted imaging. Fat-saturated T1-weighted imaging is best to appreciate intense postcontrast enhancement. •• On ultrasound, a soft tissue heterogeneous hyperechoic mass is seen with prominent vessels that display arterial and venous color flow imaging. •• On angiography, a hypervascular mass with capillary blush and without arteriovenous shunting is seen. •• Upon involution, regression of the mass with fatty replacement is seen.

■■ Essential Facts •• It is a benign vascular neoplasm of proliferating endothelial cells that is generally a single lesion in the subcutaneous tissue. It can occur in parotid space, face, neck, orbit, or nasal cavity. •• It is not seen at the time of birth but may present as early as at 2 weeks. •• It presents in infancy as a well-defined mass with high flow vessels in proliferative phase that continues for 1 to 2 years. It can involute with fatty replacement over next few years, to be complete by late childhood. •• It was previously known as a capillary hemangioma. It should not be confused with a vascular malformation like venous malformation, venolymphatic malformation, or arteriovenous malformation (AVM). But it can be a part of PHACES syndrome. •• Due to spontaneous involution, a majority of cases do not require any treatment. The surgical excision and embolization is indicated in case of airway compromise or optic nerve compression if intraorbital.

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� Pearls & � Pitfalls ÛÛ A well-defined, intensely enhancing mass of infancy,

which is not present at birth, does not show any phleboliths or café au lait skin spots. ÛÛ It does not require any treatment with 90% involuting by the age of 9 years. ÚÚ Large vessels with ill-defined parenchymal mass favors AVM.

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Case 87

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■■ Clinical Presentation A 62-year-old woman presents with difficulty swallowing.

■■ Further Work-up An additional study was obtained.

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■■ Imaging Findings

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(A) Contrast-enhanced axial CT image through the skull base demonstrates an enhancing mass lesion within the left nasopharynx (circle). (B, C) T1 precontrast (B) and T1 postcontrast (C) MRIs were also obtained. There is an aggressive soft tissue mass in the left nasopharynx (arrow) with extension into the muscles of mastication. Note the loss of the normal fat plane between the medial and lateral pterygoid muscles (asterisks). The left mastoid air cells are obstructively opacified (arrowhead). The lesion heterogeneously enhances (rectangle).

■■ Differential Diagnosis •• Nasopharyngeal carcinoma (NPC): An aggressive lesion centered within the nasopharynx should be viewed with suspicion as this entity. •• Squamous cell carcinoma (SCCA): This lesion could represent retrograde spread of a lesion based within the oropharynx. •• Metastasis/myeloma: Due to the presence of lymphoid tissue in the adenoids, this entity must also be considered.

•• CT and MRI features are those of an aggressive mass lesion centered within the nasopharynx. •• Tumors may extend superiorly into the cranium via the petroclival fissure. Perineural spread may also occur.

■■ Other Imaging Findings •• Some tumors may be FDG avid. However, routine use of PET examinations has not been established.

■■ Essential Facts

� Pearls & � Pitfalls

•• NPC is a unique disease entity unrelated to smoking or alcohol exposure (in contrast to other SCCA of the upper aerodigestive tract). •• Positive correlation with Epstein–Barr virus (EBV) infection and ingestion of salted fish; increased incidence in Southeast Asians. •• May present insidiously, related to involvement of various structures in the nasopharynx, including cranial nerve palsies, masticator space dysfunction, or otitis media from eustachian tube dysfunction.

ÛÛ May present as adenopathy in a patient with unknown

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primary. Careful radiographic evaluation of this region is thus warranted. ÚÚ Perineural spread may be discontiguous. Careful intracranial evaluation is required in NPC patients for such tumor extension.

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Case 88

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■■ Clinical Presentation A 9-month-old presents with respiratory tract infection and recurrent preauricular swelling.

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(A, B) Postcontrast axial CT exhibits a rounded low attenuating mass at the superficial lobe of the parotid gland with peripheral ring enhancement (black arrow). There is mild patchy enhancement of the swollen left parotid gland (black arrow).

■■ Differential Diagnosis

■■ Other Imaging Findings

•• Infected first branchial cleft cyst: Ovoid, well-marginated cystic mass in an infant or child is seen within the parotid gland with peripheral postcontrast enhancement and inflammatory changes within the parotid gland. •• Suppurative intraparotid lymph node: Well-marginated, ovoid cystic mass within the parotid gland. If single, it is difficult to differentiate from infected first branchial cleft cyst. •• Lymphatic malformation: Also known as cystic hygroma, this appears as a multilocular mass with serpiginous, tubular, cystic channels. It also involves other neck spaces, rarely only the parotid space and rarely single.

•• Contrast-enhanced CT scan is most diagnostic. A wellmarginated, ovoid, nonenhancing low-density mass is seen. However, when infected, a thick rim-enhancing lesion is visualized along with inflammatory changes within the parotid gland. •• On ultrasound, an anechoic mass with posterior acoustic enhancement is seen within the parotid space or in the region of the external auditory canal (EAC). •• On MRI, a low T1 and high T2 signal mass is seen within the parotid gland or periparotid area. On postcontrast imaging, the wall enhances only in the case of an infected first branchial cleft cyst.

■■ Essential Facts

� Pearls & � Pitfalls

•• Caused by persistence of first branchial apparatus, is relatively rare, and accounts for 8 to 10% of branchial cleft anomalies. It is more commonly discovered in infancy or childhood but can present at any age. •• When not infected, it is relatively asymptomatic and may present as a compressible mass in parotid or periparotid area. •• When diagnosed as an abscess, it is often surgically drained; however, recurrence is common. •• Complete surgical resection is treatment of choice.

ÛÛ Repeated respiratory tract infection and recurrent

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parotid swelling in infancy and childhood calls for further cross-sectional imaging with contrast-enhanced CT scan. ÚÚ The treatment of choice is complete surgical resection; however, the proximity of the facial nerve is an added risk.

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Case 89

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■■ Clinical Presentation A 42-year-old woman presents with throat mass.

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■■ Imaging Findings

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(A–C) Axial MRIs of the oropharynx were obtained including axial T1 postcontrast with fat suppression (A), axial T2 with fat suppression (B), and axial DWI (C). There is a homogeneous, mildly enhancing, well-demarcated T2 hypointense mass lesion along the expected location of the left tonsil. Lesion demonstrates increased DWI signal (arrows).

•• Tonsillar lymphoma: Tonsillar tissue is rich in lymphatics and thus a possible location for lymphoma. Lymphomas tend to be more homogenous than other tonsillar tumors. •• Squamous cell carcinoma (SCCA): Most soft tissue masses of the tonsils are SCCA. However, they are usually more heterogeneous. •• Salivary gland tumor: Although these can be present in the oropharynx, the tonsil is an uncommon location.

•• Presentation can be related to the structure involved (throat mass in this case). One may also encounter constitutional symptoms such as fever, night sweats, and weight loss. Additional nodal sites of involvement may also occur. •• On imaging, lymphomas may be relatively T2 hypointense on MRI, similar to normal tonsillar tissue. Most demonstrate at least mild contrast enhancement. Lesions tend to be more homogeneous in comparison to SCCA. •• Lesions may also restrict diffusion.

■■ Essential Facts

■■ Other Imaging Findings

•• Lymphomas can be divided into Hodgkin disease (HD) and non-Hodgkin lymphoma (NHL) based on the presence of Reed-Sternberg cells. NHL does not contain such cells and is more commonly noted within the extranodal head and neck regions in comparison to HD. •• NHL is a disease process more commonly found in older adults (. 50 years old); the vast majority are B cell line neoplasms. •• Waldeyer’s ring (adenoids, tonsils, and lingual tonsils) is a common location for extranodal lymphoma within the head and neck due to the presence of a rich lymphatic network.

•• FDG-PET has been used to monitor response to therapy in NHL patients.

■■ Differential Diagnosis

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� Pearls & � Pitfalls ÛÛ Enlarged tonsillar tissue should prompt correlation

with direct inspection, as lymphoma can have a rather benign appearance radiographically. ÚÚ If NHL is present, full stage radiographic work-up must be performed to assess for all sites of disease.

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Case 90

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■■ Clinical Presentation A 42-year-old man presents with decreased libido, galactorrhea, and headaches.

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■■ Imaging Findings

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■■ Differential Diagnosis •• Pituitary macroadenoma with cavernous sinus invasion: An intrasellar soft tissue mass isointense to the gray matter on both T1- and T2-weighted imaging with low contrast uptake than normal pituitary gland on postcontrast imaging. The normal pituitary gland is not separately identifiable from the mass on most sequences, except postcontrast imaging. The mass envelopes the intracavernous ICA but does not cause narrowing of the lumen. •• Cavernous sinus meningioma: An intensely enhancing mass, isointense to gray matter on both T1- and T2-weighted imaging that arises from the lateral wall of cavernous sinus, extends into the sella, and displays a dural tail along the clivus and tentorium. The mass frequently envelopes the intracavernous ICA and can cause narrowing of the lumen. •• Sellar/parasellar hemangioma: A vasoformative neoplasm arising from the lateral wall of the cavernous sinus that can extend into the sella. It displays high T2 signal and intense postcontrast enhancement.

■■ Essential Facts •• Pituitary macroadenomas are usually slow-growing benign masses. •• The invasive pituitary adenomas are more commonly seen in middle age and account for ~35% of all the pituitary tumors. •• The invasive pituitary macroadenomas are generally gonadotropin cell adenomas or giant prolactinomas in men. •• They are generally indistinguishable from normal pituitary gland and may exhibit suprasellar extension through the diaphragma sellae.

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(A) Noncontrast axial CT shows an expansile, mildly hyperdense sella turcica mass with remodeling and posterior displacement of the dorsum sella with erosion of its left side (arrow). The mass also extends laterally on the left side into the expected location of the left cavernous sinus. (B) T1-weighted coronal MRI exhibits a soft tissue mass isointense to gray matter, arising in the left side of the pituitary gland and extending inferiorly into the sphenoidal sinus with a breach of the floor of the sella turcica. The mass also extends laterally into the left cavernous sinus (arrow) and 75% surrounds the intracavernous left internal carotid artery (ICA). The pituitary stalk is deviated toward the right. (C) T2-weighted coronal MRI exhibits the mass to be isointense to gray matter (arrow). The normal pituitary parenchyma displays lower signal than the mass. (D) Postcontrast T1-weighted coronal MRI exhibits that the left lateral mass has less contrast uptake (arrowhead) than normal pituitary gland, as seen on the right side of the sella turcica. There is no evidence of narrowing of the intracavernous ICA.

•• Surgical resection with and without radiation therapy is the treatment of choice.

■■ Other Imaging Findings •• On CT, an irregular, soft tissue mass, iso- to hyperdense to gray matter centered in the sella turcica with invasion of surrounding bone and soft tissue is seen. On contrastenhanced CT, moderate, inhomogeneous enhancement of the mass is seen. Expansion and erosion of the floor of sella turcica is common in invasive macroadenoma. Invasion of the sphenoidal sinus and destruction of the upper clivus can also be seen. •• On MRI, the mass is usually isointense to gray matter on both T1- and T2-weighted images. On postcontrast imaging, they enhance heterogeneously and absorb less contrast than normal pituitary gland, which is discerned better on this sequence than any other. On invasion of cavernous sinus, it can envelope the internal carotid artery but does not cause narrowing of its lumen.

� Pearls & � Pitfalls ÛÛ Adult male with hormonal disturbance and invasive,

destructive sellar/parasellar mass raises high suspicion for a locally invasive pituitary macroadenoma. When a mass invading the central skull base and cavernous sinuses is contiguous with soft tissue in the sella, the possibility of pituitary macroadenoma may be considered. ÚÚ In rare cases, an invasive pituitary adenoma can cause narrowing of the intracavernous ICA.

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Case 91

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■■ Clinical Presentation A 16-year-old boy presents with seizures.

■■ Further Work-up An additional test was performed.

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(A–D) Sagittal and coronal T1-weighted MRIs demonstrate anterior and inferior displacement of brain tissue (curved white arrow) into the expected location of the ethmoid air cells (white arrow). Bone window head CT demonstrates a bony defect along the floor of the anterior cranial fossa (black arrow) with additional defects along the left orbital rim (arrowhead) and left frontal bone (curved black arrow).

■■ Differential Diagnosis •• Encephoalcele: Brain contents are seen directly herniating into the osseous defect on MRI and CT scans.

■■ Essential Facts •• Uncommon, usually congenital (although can be posttraumatic) hernation of meninges (meningocele) or brain (encephalocele) through a bony defect. •• Anterior cephaloceles can present in a variety of ways depending on where the lesion is located. Ethmoidal lesions can present as “nasal cavity masses.” If there is dural rupture, a CSF leak or meningitis may be seen.

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•• Other midline congenital anomalies of the face and brain may also occur in such patients. •• CT clearly shows the osseous defect. MRI is superior in demonstrating herniated contents. •• Treatment is surgical.

� Pearls & � Pitfalls ÛÛ Check for other midline anomalies, such as cleft lip/ palate and corpus callosum abnormalities.

ÚÚ Caution must be used in evaluating the cribriform plate

region for defects in neonates, as ossification is not present at birth. MRI may be more helpful in such cases.

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Case 92

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■■ Clinical Presentation A 45-year-old woman presents with headaches for the last 3 to 4 years and new onset left cranial nerve VI palsy.

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■■ Differential Diagnosis •• Chondrosarcoma of skull base: An intensely high T2 signal and heterogenously enhancing skull base mass, centered at left petroclival fissure invading the clivus and petrous temporal bone. Foci of low T2 signal within the mass likely represent characteristic chondroid calcification. •• Chordoma of clivus: Low T1 and high T2 signal mass with intense postcontrast enhancement is more likely to be in midline than along the petroclival fissure. It lacks the characteristic chondroid calcification but may display bone fragments within the matrix. •• Skull base meningioma: It is associated with hyperostosis and sometimes calcification within the soft tissue mass that can mimic chondroid matrix. Bone destruction is rare. However, it exhibits homogeneous postcontrast enhancement with presence of dural tail and low to intermediate signal on T2-weighted MRI. •• Plasmacytoma: It arises from midline, involving clivus with low T2 and intermediate T1 signal. More than half are associated with multiple myeloma.

(A) T1-weighted axial MRI exhibits an irregular low T1 signal mass at left petroclival fissure (arrow), extending into the clivus as well as the left petrous temporal bone. (B) T2-weighted axial MRI exhibits a markedly hyperintense mass (arrow) with a few hypointense foci within. Note the exophytic intracranial extension into the left side of the posterior fossa. (C) Postcontrast T1-weighted axial MRI exhibits intense but somewhat heterogeneous postcontrast enhancement (arrow). (D) Postcontrast, fatsaturated, T1-weighted axial MRI better defines the extent and bony invasion of the enhancing mass (arrow).

•• Most of these masses are slow-growing and locally aggressive. Distal metastasis is rare. •• A combination of radical resection and radiation therapy is treatment of choice. However, total surgical resection in this region is challenging due to high morbidity and proximity of neurovascular structures.

■■ Other Imaging Findings •• On CT scan, an irregular soft tissue mass with heterogeneous postcontrast enhancement and characteristic chondroid calcification within the tumor matrix is seen. Invasion of adjacent clivus and petrous temporal bone is well evaluated on bone windows. •• On MRI, a very high T2 signal mass with presence of hypointense intratumoral foci of calcification is characteristic. On T1-weighted imaging, low to intermediate signal intensity is seen. Intense but heterogeneous postcontrast enhancement is common. •• On angiography, the mass appears to be relatively hypovascular.

■■ Essential Facts

� Pearls & � Pitfalls

•• Chondrosarcoma accounts for ~5% of all the skull base tumors. A majority of these arise from the petroclival fissure. •• It is more commonly seen in middle-aged patients and presents with long-standing headaches. •• Invasion of clivus leads to cranial nerve VI palsy. However, involvement of cranial nerves VII, VIII, V, and III is also possible.

ÛÛ Characteristic MR appearance includes markedly high

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T2 signal mass with hypointense foci and heterogeneous postcontrast enhancement at petroclival fissure. CT scan of the skull base can additionally show chondroid calcification and bone destruction. ÚÚ Locally aggressive skull base masses like plasmacytoma or metastasis can mimic chondrosarcoma, especially when the tumor matrix cannot be well evaluated.

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Case 93

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■■ Clinical Presentation A 3-month-old presents with difficulty in passing a nasogastric tube.

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(A, B) Noncontrast bone window axial CT images were obtained through the head. There is a bony plate along the expected location of the right nasal choana (arrows).

•• Choanal atresia: Atresia of the nasal choana that can be unilateral or bilateral, bony or membranous.

•• Treatment is surgical, which may require revisions over time. •• CT is the method of choice in evaluating for atresia. Nasal airway should preferably be clear of secretions.

■■ Essential Facts

� Pearls & � Pitfalls

•• Congenital choanal atresia may be bony or membranous. •• Bilateral involvement presents in the neonatal period due to cyclical cyanosis relieved by crying (as newborns are obligate nasal breathers). •• Unilateral involvement may go undiagnosed for years. •• May be isolated or seen in conjunction with other anomalies, such as CHARGE (coloboma, heart defects, choanal atresia, growth retardation, genitourinary anomalies, ear anomalies).

ÛÛ High index of suspicion for bilateral atresia in neonates

■■ Differential Diagnosis

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with cyclical cyanosis.

ÚÚ Unilateral choanal atresia may go undiagnosed, unless the radiologist looks for it on every exam.

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Case 94

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■■ Clinical Presentation A 24-year-old, in a high-speed motor vehicle accident, presents with hemotympanum and loss of consciousness.

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(A, B) High-resolution axial temporal bone CT exhibits a linear lucency (arrow) parallel to the long axis of the petrous temporal bone through the mastoid air cells extending into the middle ear cavity. An isolated truncated ossicle in the epitympanum is likely the body of incus (arrow). (C) High-resolution coronal temporal bone CT exhibits dehiscent fracture across the mastoid air cells with fracture of the tegmen tympani and parietal bone. A prolapsed ossicle (arrow) is seen in mesotympanum.

■■ Differential Diagnosis •• Longitudinal temporal bone fracture: An extralabyrinthine lucency parallel to the long axis of the petrous temporal bone is seen following a blunt trauma with ossicular injury. Extensive opacification of mastoid air cells and middle ear cavity secondary to either hemorrhage or cerebrospinal fluid (CSF) otorrhea is seen. •• Transverse temporal bone fracture: A lucency perpendicular to the long axis of petrous temporal bone is seen with possible involvement of the otic capsule following blunt trauma. •• Mixed temporal bone fracture: Both longitudinal and transverse lucencies, often causing injury to auditory ossicles and the otic capsule, are seen following polytrauma.

■■ Essential Facts •• Fracture of the temporal bone is the most common fracture of the skull base and is seen in ∼20% of the patients with skull fractures. •• Longitudinal fractures account for 70 to 90% of temporal bone fractures and occur secondary to a lateral impact blunt trauma. •• The fracture line often involves the external auditory canal and frequently courses lateral to the carotid canal near the foramen spinosum. •• The fracture may involve the tegmen tympani and tegmen mastoideum with increasing risk for CSF leak and meningitis. •• Ossicular disruption, most commonly incudomalleolar dissociations, often results in conductive hearing loss.

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Facial nerve paralysis can result from involvement of the facial nerve canal. •• Treatment of the longitudinal fracture may be directed toward repair of CSF otorrhea, ossicular bone reconstruction, antibiotics to prevent meningitis, and prevention of facial nerve paralysis by decompressing the facial nerve.

■■ Other Imaging Findings •• The fractures of the temporal bone are best imaged on axial, high-resolution, thin section (1 to 1.25 mm in thickness) CT scans with coronal reconstructions. Opacification of mastoid air cells, fracture of the external auditory canal, involvement of the facial nerve canal, and incudomalleolar dissociations are better evaluated with high-resolution CT scan. •• MRI has poor specificity in identifying temporal bone fractures. However, it may be helpful in identifying associated temporal contusion and other brain parenchymal changes.

� Pearls & � Pitfalls ÛÛ Patients with longitudinal fractures of the temporal

bone are at an increased risk of developing cholesteatoma due to deposition of squamous epithelial debris into the middle ear along the fracture line. ÚÚ A newer classification of temporal bone fractures on the basis of whether the otic capsule is involved or spread is suggested; however, it is not considered better in predicting the likelihood of sustaining specific injuries.

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Case 95

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■■ Clinical Presentation A 32-year-old man presents with bilateral facial fullness.

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(A) Contrast-enhanced axial CT images were obtained through the facial bones. There are small fluid collections within the parotid glands bilaterally (black arrows). The palatine tonsils are also enlarged (white arrows).

■■ Differential Diagnosis •• Benign lymphoepithelial cyst (BLC): In a patient with known HIV, this is the diagnosis. HIV infection is suggested by tonsillar enlargement. •• Bilateral Warthin tumors: Most of these lesions have at least some soft tissue component, and tonsillar enlargement would not be present. •• Sjögren syndrome: Imaging findings may be nearly identical to BLC, but there would be a different clinical setting. Tonsillar enlargement would not be present.

•• Medical treatment of HIV disease tends to cause regression of these lesions as well. •• On MRI or CT, lesions can be noted throughout the parotid glands with variable amounts of cystic and solid components. These lesions are most commonly noted bilaterally.

� Pearls & � Pitfalls ÛÛ Finding of BLC and tonsillar/adenoidal/lymph node enlargement strongly suggests HIV infection.

ÚÚ In isolation, Sjögren syndrome can appear quite similar. ■■ Essential Facts •• Intraparotid cystic or mixed solid-cystic process of unknown etiology seen in the HIV population. •• Can present as bilateral fullness in these areas and may also be painful. This may be the presenting sign of HIV infection.

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Case 96

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■■ Clinical Presentation A 42-year-old man presents with painful, enlarging soft tissue mass over his right mandible.

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■■ Differential Diagnosis •• Masticator space sarcoma: A large, heterogeneous, aggressive, masticator space mass with new bone formation, seen on both sides of the mandibular ramus with destruction and infiltration, is seen on CT scan. On MRI, a large, heterogeneous, poorly marginated masticator space mass that appears to be hyperintense to muscle displays heterogeneously high T2 signal postcontrast enhancement. •• Invasive squamous cell carcinoma: An aggressive squamous cell carcinoma of the retromolar trigone or palatine tonsil can invade the masticator space. However, there is no new bone formation. It also displays mildly high T2 signal with patchy postcontrast enhancement. •• Masticator space venolymphatic malformation: Multiloculated high T2 signal, irregular mass is seen with presence of calcified phleboliths. •• Mandibular metastatic deposit: An aggressive, large, heterogeneous, masticator space mass is seen with bone destruction but without intratumoral calcification.

■■ Essential Facts •• Seen in middle age with male preponderance, it accounts for ~5% of total sarcomas. •• It could be primarily an osteosarcoma, synovial sarcoma, Ewing sarcoma, chondrosarcoma, fibrosarcoma, or rhabdomyosarcoma. •• Most common etiology is prior radiation of this region to treat other possible tumors. Family history of Gardner syndrome, Li-Fraumeni syndrome, or inherited

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(A) Postcontrast axial CT shows a mildly enhancing, heterogeneous, aggressive, irregular mass with infiltrating margins (arrows) surrounding the right mandibular ramus. (B) Bone window of axial CT exhibits formation of new bone within the mass. (arrowheads) (C) T1-weighted axial MRI shows a large, lobulated, soft tissue mass (arrow) hyperintense to muscles, surrounding the right mandibular ramus and involving the masseter and pterygoid muscles (arrow). (D) T2-weighted axial MRI exhibits a heterogeneously high T2 signal mass (arrow) infiltrating the masticator space. (E) Postcontrast, fat-saturated, T1-weighted axial MRI exhibits intense heterogeneous enhancement of this mass (arrow).

retinoblastoma is associated with increased incidence of masticator space sarcoma. •• A combination of surgery and radiotherapy is utilized to treat the masticator space sarcoma, depending on the staging at the time of diagnosis.

■■ Other Imaging Findings •• On CT scan, a large, heterogeneous, aggressive, irregular, and poorly marginated masticator mass with extension into adjacent spaces of the neck and invasion of surrounding bony and neurovascular structures is seen. The bone window can exhibit abnormal calcification or ossification as well as subtle invasion of surrounding bony structures. •• MRI can evaluate invasion of surrounding soft tissues as well as subtle bone marrow changes of the mandible to evaluate for mandibular invasion. Perineural spread, especially along the cranial nerve V3, is frequently seen and detected early on MRI.

� Pearls & � Pitfalls ÛÛ A large masticator mass—in the absence of other head

and neck malignancy, other systemic malignancy, or clinical symptomatology of an abscess—favors the possibility of masticator space sarcoma. ÚÚ The incidence of perineural spread, especially along cranial nerve V3, is very high. The region of inferior alveolar canal, mandibular foreman, foramen ovale, and Meckel’s cave should be carefully evaluated to look for possible perineural spread.

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Case 97

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■■ Clinical Presentation A 25-year-old man presents with several months history of neck pain and increasing kyphosis.

■■ Further Work-up An additional exam was obtained.

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■■ Differential Diagnosis •• Spinal tuberculosis (TB): Process involving many vertebrae and the presence of adjacent fluid collections suggest this diagnosis. •• Bacterial osteodiskitis: Also a possibility. However, adjacent involved levels would likely show more involved endplate erosion. •• Metastasis: This process is too destructive at this point to be neoplastic. Earlier in the disease, similar imaging findings may be present.

■■ Essential Facts •• Most common manifestation of musculoskeletal tuberculosis; most commonly seen in the thoracic spine. •• Symptoms are similar to pyogenic osteodiskitis, but one may also see signs of systemic/pulmonary disease if present. Additionally, loss of vertebral height is more common, with development of kyphosis. •• Bone fragmentation and kyphosis may also lead to neurologic sequelae. •• Imaging findings may appear similar to bacterial disease. However, a few more specific findings may suggest the diagnosis.

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(A–C) Sagittal T2 (A) and sagittal and axial T1 postcontrast enhanced (B, C) MRIs. There is a low T1/T2 signal focus centered at the C6 level (circles) with adjacent rim-enhancing collections (white arrows). (D) Cervical spine CT demonstrates the area of signal dropout to represent sclerotic fused bone (black arrow). There is an abrupt kyphosis at this level with areas of adjacent bony demineralization (arrowhead) and relatively intact adjacent vertebral endplates.

•• As in pyogenic osteodiskitis, lesions on CT demonstrate erosive endplate changes. However, in spinal TB, disk space height is usually preserved early in the disease process and multiple discontiguous levels may be involved. •• Paravertebral abscesses along the spine within the adjacent musculature (such as the psoas muscles) are also a hallmark of spinal TB, particularly if calcification is present. •• Similar to bacterial disease, MRI demonstrates T1/T2 prolongation with enhancement of the involved structures. Subligamentous spread, however, can occur in spinal TB.

■■ Other Imaging Findings •• Technetium 99m MDP bone scans are not reliable for the diagnosis of spinal TB due to low sensitivity.

� Pearls & � Pitfalls ÛÛ Paraspinal collections, particularly if calcifications are present, suggest the disease.

ÚÚ Imaging features are often similar to pyogenic osteodiskitis.

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Case 98

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■■ Clinical Presentation A 46-year-old woman presents with long-standing headaches and periorbital pain.

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(A) T1-weighted axial MRI exhibits a soft tissue mass isointense to gray matter involving the right cavernous sinus (arrow) with an exophytic extension into prepontine cistern. There is mild narrowing of the intracavernous right internal carotid artery (ICA) with mass effect on the right side of the ventral surface of pons. (B) T2-weighted axial MRI exhibits the soft tissue mass to be isointense to gray matter (arrow). (C) Postcontrast T1-weighted axial image exhibits intense postcontrast enhancement of the right cavernous sinus mass (arrow) as well as the exophytic component layering on the dorsal surface of clivus. There is thickening along both sides of the lateral dural wall of the right cavernous sinus, which appears as a hypointense line. Mild narrowing of the right ICA is also seen. (D) Postcontrast T1-weighted coronal image exhibits the right cavernous sinus mass enveloping the intracavernous right ICA (arrow).

■■ Differential Diagnosis •• Cavernous sinus meningioma: A homogeneously and intensely enhancing soft tissue mass arising from the lateral wall of the cavernous sinus that appears to be isointense to gray matter on both T1- and T2-weighted images with a dural tail along the clivus and tentorium extending away from the edge of the tumor. The mass envelopes the intracavernous right ICA and may cause narrowing of its lumen. •• Cavernous sinus schwannoma: They more commonly originate from the trigeminal nerve within the Meckel’s cave and extend anteriorly to involve the lateral wall of the cavernous sinus. There are well-marginated, benign masses that display high T2 signal. •• Pituitary macroadenoma: Pituitary macroadenoma may grow laterally and invade the cavernous sinus. However, it is difficult to determine, as the mass is indistinguishable from the pituitary gland. Presence of abnormal soft tissue between the lateral wall of the cavernous sinus and ICA or tumor extension lateral to the top of ICA are reliable signs. Unlike meningiomas, pituitary adenomas generally do not cause narrowing of the ICA. •• Cavernous hemangioma: It is more commonly seen in elderly female patients. They display high T1 and high T2 signal and originate from the lateral wall of cavernous sinus. They are composed of sinusoidal spaces with slow flowing or stagnant blood and exhibit late filling in after contrast.

•• Like all intracranial meningiomas elsewhere, it is more commonly seen in middle age with female preponderance. •• It can be a part of the syndrome of neurofibromatosis type 2 (NF2), in which case there could be meningiomas elsewhere in the cranial cavity. •• Surgical treatment is often associated with the high risk of morbidity and mortality. Radiation treatment can contain the growth of the tumor and is many times the preferred treatment.

■■ Other Imaging Findings •• On CT scan, there is a convex outer margin of the cavernous sinus on postcontrast imaging. •• On MRI, the mass appears to be isointense to cerebral gray matter on all the sequences and exhibits intense homogeneous postcontrast enhancement. A dural tail is frequently seen extending from the edge of the tumor into the ipsilateral leaflet of the tentorium cerebelli. •• The lateral dural wall of the cavernous sinus can sometimes be seen within the thickened and intensely enhancing mass. •• Meningiomas can cause constriction of the lumen of the intracavernous ICA unlike pituitary microadenoma or schwannoma.

� Pearls & � Pitfalls ÛÛ Presence of a dural tail along the clivus or tentorium

■■ Essential Facts •• Cavernous sinus meningioma is the second most common neoplasm with unilateral involvement of the cavernous sinus after pituitary macroadenoma.

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and constriction of the ICA favors the diagnoses of meningioma. ÚÚ A meningioma can extend inside the cavernous sinus and Meckel’s cave and then into the prepontine cistern, mimicking a schwannoma.

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Case 99

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■■ Clinical Presentation A 42-year-old man presents with painless slow bulging and inferior medial displacement of the left orbital globe.

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(A, B) Contrast-enhanced axial CT scan shows well-circumscribed, moderately and homogeneously enhancing mass (white arrow) in the anterior superotemporal extraconal compartment of the left orbital cavity. There is mild remodeling of the fossa for lacrimal gland. (C) Postcontrast, fat-saturated, T1-weighted coronal MR image exhibits intensely and homogeneously enhancing, ovoid mass (white arrow) in supratentorial extraconal compartment of the left orbital cavity.

■■ Differential Diagnosis •• Pleomorphic adenoma of lacrimal gland: A well-circumscribed, oval, solid, moderately enhancing soft tissue mass at superolateral medial, extraconal orbital cavity with scalloping of lacrimal fossa on CT and inferomedial displacement with proptosis of orbital globe in a patient with painless, slowly progressive proptosis most likely represents a pleomorphic adenoma of the lacrimal gland. •• Adenoid cystic carcinoma: It is the second most common lacrimal epithelial mass, commonly presenting in the fourth decade of life with minimal proptosis of orbital globe but presence of an ill-defined, painful mass in superotemporal part of the orbital cavity. Bony erosion and areas of calcification are more commonly seen. •• Lymphoproliferative disease: It constitutes up to 50% of non-epithelial lacrimal lesions. Malignant lymphoma is more common, commonly presenting in the seventh decade of life. Irregular in shape, it generally molds to the shape of the globe. It appears mildly hyperdense on any CT and displays hypointense T2 signal on MRI. •• Inflammatory pseudotumor: Painful, tender, palpably enlarged lacrimal gland. Diffuse enlargement of the gland with stranding of fat at the margins of the mass is seen on imaging.

■■ Essential Facts •• Pleomorphic adenoma is the most common benign neoplasm of the lacrimal gland, accounting for about 30% of lacrimal gland lesions and 2% of all the orbital neoplasms. •• It more commonly manifests in 4th or 5th decade of life, at a younger age than malignant neoplasms. The risk of malignant transformation is low.

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•• En bloc complete surgical excision without biopsy is the treatment of choice, with excellent prognosis. Capsular rupture or incomplete expiration may lead to recurrence or malignant transformation.

■■ Other Imaging Findings •• On CT, scalloped bony remodeling of lacrimal fossa is characteristic. Presence of punctate calcification is seen in about one-third of cases. •• On MRI, hypointense to isointense T1 signal and isointense to hyperintense T2 signal with moderate to intense contrast enhancement of a well-circumscribed round or oval mass is characteristic. •• Presence of secondary cystic degeneration, hemorrhage, and serous or mucous collections is seen in larger masses. •• Bone erosion is rare and suggests underlying malignancy. •• Infiltrative margins and nodularity also indicate underlying malignancy.

� Pearls & � Pitfalls ÛÛ Slowly progressive and painless proptosis in the 2nd to

5th decades of life with inferomedial displacement of orbital globe is characteristic presentation. ÛÛ Well-circumscribed margins, round or oval shape, scalloping of lacrimal fossa, and moderate to intense postcontrast enhancement are characteristic imaging findings. ÛÛ Presence of pain indicates underlying malignancy. ÚÚ Early lesions of adenoid cystic carcinoma may be indistinguishable from pleomorphic adenoma.

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Case 100

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■■ Clinical Presentation A 55-year-old white man presents with difficulty in breathing, nasal pain, nasal obstruction, and epistaxis.

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(A) Coronal noncontrast CT of the paranasal sinus exhibits a mildly hyperattenuating expansile soft tissue mass at the right nasal cavity eroding the right lamina papyracea (arrow) and bulging into the right orbital cavity. (B) T1-weighted axial MRI exhibits the expansile right nasal cavity mass to be mildly hyperintense to muscles (arrow). (C) T2-weighted axial MRI exhibits a low T2 signal expansile right nasal cavity mass (arrow). High T2 signal right maxillary mucosal disease is seen. (D) Postcontrast T1-weighted coronal MRI shows patchy postcontrast enhancement of the mass (arrow).

■■ Differential Diagnosis •• Sinonasal melanoma: An expansile soft tissue mass more in the nasal cavity than maxillary sinus, with bone destruction, involving the nasal septum and the lateral nasal wall is seen on CT scan. On MRI, the mass exhibits low T2 signal. A low T2 signal and high T1 signal on MRI is likely due to presence of free radicals, metal ions, or melanin. Avid postcontrast enhancement is also seen. •• Squamous cell carcinoma: It more commonly arises in the maxillary antrum and then extends into the nasal cavity. It can also result in much more aggressive bone destruction and appears to be much more heterogeneous. •• Sinonasal lymphoma: A primary nasal cavity mass is seen with bone destruction and remodeling. It is a homogeneous solid soft tissue mass that can exhibit low T2 signal and mild hyperattenuation on CT scan. •• Esthesioneuroblastoma: A superior nasal cavity mass, it is seen with relation to the cribriform plate, prominently arising from the olfactory mucosa. Areas of cystic degeneration and presence of an intracranial cyst at the tumor–brain interface can also be seen.

■■ Essential Facts •• It arises from the melanocytes of the neural crest origin that migrate to sinonasal epithelium and account for ∼1% of total melanomas and 5% of all the sinonasal masses. •• It is a dark pink, highly vascular mass with varying degree of melanin deposits. •• More than 90% occur in the white population with male preponderance; more common in the fifth to eighth decade of life.

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•• Rapidly metastasizes to lungs, lymph nodes, and brain with poor prognosis and mean survival of ~24 months. •• Aggressive radical surgical resection and radiotherapy are treatments of choice.

■■ Other Imaging Findings •• On CT scan, a lobular primary nasal cavity mass with bone destruction and remodeling is seen. The nasal septum, lateral wall, and inferior turbinate of the nasal cavity are preferentially involved. Secondary extension into the maxillary sinus or orbital cavity is frequently seen. •• On MRI, the signal intensities can change with varying degree of melanoma deposits. Melanotic melanoma exhibits high T1 and low T2 signal; however, amelanotic melanoma exhibits intermediate T1 signal with variable low to high T2 signal. Areas of possible hemorrhage can exhibit susceptibility artifact on gradient echo T2-weighted imaging. On postcontrast imaging, there is intense enhancement of the mass.

� Pearls & � Pitfalls ÛÛ A lower nasal cavity, aggressive solid mass that exhibits low T2 and high T1 signal with bone destruction is the classical imaging appearance. ÛÛ A pigmented appearance on nasal endoscopy favors melanoma. ÚÚ If the melanin content is low, sinonasal melanoma can appear very similar to a nasal polyp on noncontrast CT.

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Further Readings Case 1 LeBedis CA, Sakai O. Nontraumatic orbital conditions: diagnosis with CT and MR imaging in the emergent setting. Radiographics 2008;28(6):1741–1753

Case 2 Derdeyn CP, Moran CJ, Wippold FJ II, Chason DP, Koby MB, Rodriguez F. MRI of esthesioneuroblastoma. J Comput Assist Tomogr 1994;18(1):16–21 Yu T, Xu YK, Li L, et al. Esthesioneuroblastoma methods of intracranial extension: CT and MR imaging findings. Neuroradiology 2009;51(12):841–850

Case 3 Kapur R, Sepahdari AR, Mafee MF, et al. MR imaging of orbital inflammatory syndrome, orbital cellulitis, and orbital lymphoid lesions: the role of diffusion-weighted imaging. AJNR Am J Neuroradiol 2009;30(1):64–70 LeBedis CA, Sakai O. Nontraumatic orbital conditions: diagnosis with CT and MR imaging in the emergent setting. Radiographics 2008;28(6):1741–1753

Case 4 Codreanu CM, Duet M, Hautefort C, et al. Endolymphatic sac tumors in von Hippel-Lindau disease: report of three cases. Otol Neurotol 2010;31(4):660–664 Diaz RC, Amjad EH, Sargent EW, Larouere MJ, Shaia WT. Tumors and pseudotumors of the endolymphatic sac. Skull Base 2007;17(6):379–393

Case 5 LeBedis CA, Sakai O. Nontraumatic orbital conditions: diagnosis with CT and MR imaging in the emergent setting. Radiographics 2008;28(6):1741–1753

Case 6 Ramina R, Maniglia JJ, Fernandes YB, et al. Jugular foramen tumors: diagnosis and treatment. Neurosurg Focus 2004;17(2):E5 Razek AA, Huang BY. Soft tissue tumors of the head and neck: imaging-based review of the WHO classification. Radiographics 2011;31(7):1923–1954

Case 7 Leet AI, Collins MT. Current approach to fibrous dysplasia of bone and McCune-Albright syndrome. J Child Orthop 2007;1(1):3–17

Case 8 Kumar R, Wani AA. Unusual tumors of the posterior fossa skull base. Skull Base 2006;16(2):75–84 Macdonald AJ, Salzman KL, Harnsberger HR, Gilbert E, Shelton C. Primary jugular foramen meningioma: imaging appearance and differentiating features. AJR Am J Roentgenol 2004;182(2):373–377

Case 9 Kania RE, Sauvaget E, Guichard JP, Chapot R, Huy PT, Herman P. Early postoperative CT scanning for juvenile nasopharyngeal angiofibroma: detection of residual disease. AJNR Am J Neuroradiol 2005;26(1):82–88 Momeni AK, Roberts CC, Chew FS. Imaging of chronic and exotic sinonasal disease: review. AJR Am J Roentgenol 2007;189(6, Suppl):S35–S45

Case 10

Mazzoni A, Sanna M, Saleh E, Achilli V. Lower cranial nerve schwannomas involving the jugular foramen. Ann Otol Rhinol Laryngol 1997;106(5):370–379

Case 11 LeBedis CA, Sakai O. Nontraumatic orbital conditions: diagnosis with CT and MR imaging in the emergent setting. Radiographics 2008;28(6):1741–1753 Parmar H, Ibrahim M. Extrathyroidal manifestations of thyroid disease: thyroid ophthalmopathy. Neuroimaging Clin N Am 2008;18(3): 527–536, viii–ix

Case 12 Razek AA, Huang BY. Lesions of the petrous apex: classification and findings at CT and MR imaging. Radiographics 2012;32(1):151–173 Schmalfuss IM. Petrous apex. Neuroimaging Clin N Am 2009;19(3): 367–391

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Case 15 Mafee MF. The eye. In: Curtin HD, Som PM, eds. Head and Neck Imaging. 4th ed. St. Louis, MO: Mosby, Inc.; 2003:441–527

Case 16 Chadha V, Awan MA, Gonzalez P, Cauchi P, Roberts F, Kemp E. Orbital venous-lymphatic malformation. Eye (Lond) 2009;23(12):2265–2266 Harris GJ, Sakol PJ, Bonavolontà G, De Conciliis C. An analysis of thirty cases of orbital lymphangioma. Pathophysiologic considerations and management recommendations. Ophthalmology 1990;97(12): 1583–1592

Case 17 Mukherji SK. Pharynx. In: Curtin HD, Som PM. Head and Neck Imaging. 4th ed. St. Louis, MO: Mosby, Inc.; 2003:1465–1520

Case 18 Capra GG, Carbone PN, Mullin DP. Paranasal sinus mucocele. Head Neck Pathol 2012;6(3):369–372 Lee TJ, Li SP, Fu CH, et al. Extensive paranasal sinus mucoceles: a 15-year review of 82 cases. Am J Otolaryngol 2009;30(4):234–238

Case 19 Morón FE, Morriss MC, Jones JJ, Hunter JV. Lumps and bumps on the head in children: use of CT and MR imaging in solving the clinical diagnostic dilemma. Radiographics 2004;24(6):1655–1674

Eldevik OP, Gabrielsen TO, Jacobsen EA. Imaging findings in schwannomas of the jugular foramen. AJNR Am J Neuroradiol 2000;21(6):1139–1144

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Case 20 Ginat DT, Bokhari A, Bhatt S, Dogra V. Inflammatory pseudotumors of the head and neck in pathology-proven cases. J Neuroradiol 2012;39(2):110–115 Narla LD, Newman B, Spottswood SS, Narla S, Kolli R. Inflammatory pseudotumor. Radiographics 2003;23(3):719–729

Case 21 Yousem DM, Tufano RP. Laryngeal imaging. Magn Reson Imaging Clin N Am 2002;10(3):451–465

Case 22 Swartz JD. Lesions of the cerebellopontine angle and internal auditory canal: diagnosis and differential diagnosis. Semin Ultrasound CT MR 2004;25(4):332–352 Veillon F, Taboada LR, Eid MA, et al. Pathology of the facial nerve. Neuroimaging Clin N Am 2008;18(2):309–320, x

Case 23 Hopper KD, Sherman JL, Boal DK, Eggli KD. CT and MR imaging of the pediatric orbit. Radiographics 1992;12(3):485–503

Case 24 Anari S, Carrie S. Sinonasal inverted papilloma: narrative review. J Laryngol Otol 2010;124(7):705–715 Jeon TY, Kim HJ, Chung SK, et al. Sinonasal inverted papilloma: value of convoluted cerebriform pattern on MR imaging. AJNR Am J Neuroradiol 2008;29(8):1556–1560

Case 25 Beaman FD, Bancroft LW, Peterson JJ, Kransdorf MJ, Murphey MD, Menke DM. Imaging characteristics of cherubism. AJR Am J Roentgenol 2004;182(4):1051–1054 Jain V, Gamanagatti SR, Gadodia A, Kataria P, Bhatti SS. Non-familial cherubism. Singapore Med J 2007;48(9):e253–e257 Scholl RJ, Kellett HM, Neumann DP, Lurie AG. Cysts and cystic lesions of the mandible: clinical and radiologic-histopathologic review. Radiographics 1999;19(5):1107–1124

Case 26 Bockmühl U, Khalil HS, Draf W. Clinicoradiological and surgical considerations in the treatment of cholesterol granuloma of the petrous pyramid. Skull Base 2005;15(4):263–267, discussion 267–268 Isaacson B, Kutz JW, Roland PS. Lesions of the petrous apex: diagnosis and management. Otolaryngol Clin N Am 2007;40(3):479–519, viii

Weissman JL, Hirsch BE. Beyond the promontory: the multifocal origin of glomus tympanicum tumors. AJNR Am J Neuroradiol 1998;19(1): 119–122

Case 30 Berrettini S, Ravecca F, Volterrani D, Neri E, Forli F. Imaging evaluation in otosclerosis: single photon emission computed tomography and computed tomography. Ann Otol Rhinol Laryngol 2010;119(4):215–224 Lee TC, Aviv RI, Chen JM, Nedzelski JM, Fox AJ, Symons SP. CT grading of otosclerosis. AJNR Am J Neuroradiol 2009;30(7):1435–1439 Redfors YD, Gröndahl HG, Hellgren J, Lindfors N, Nilsson I, Möller C. Otosclerosis: anatomy and pathology in the temporal bone assessed by multi-slice and cone-beam CT. Otol Neurotol 2012;33(6):922–927

Case 31 Osborn AG, Preece MT. Intracranial cysts: radiologic-pathologic correlation and imaging approach. Radiology 2006;239(3):650–664 Rao VJ, James RA, Mitra D. Imaging characteristics of common suprasellar lesions with emphasis on MRI findings. Clin Radiol 2008;63(8):939–947

Case 32 Ho SY, Kveton JF. Acoustic neuroma. Assessment and management. Otolaryngol Clin N Am 2002;35(2):393–404, viii Spickler EM, Govila L. The vestibulocochlear nerve. Semin Ultrasound CT MR 2002;23(3):218–237

Case 33 Woo EK, Connor SE. Computed tomography and magnetic resonance imaging appearances of cystic lesions in the suprahyoid neck: a pictorial review. Dentomaxillofac Radiol 2007;36(8):451–458

Case 34 Sennaroglu L, Saatci I. A new classification for cochleovestibular malformations. Laryngoscope 2002;112(12):2230–2241 Shah LM, Wiggins RH III. Imaging of hearing loss. Neuroimaging Clin N Am 2009;19(3):287–306

Case 35 Lowe LH, Vézina LG. Sensorineural hearing loss in children. Radiographics 1997;17(5):1079–1093

Case 36

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Khoury NJ, Naffaa LN, Shabb NS, Haddad MC. Juvenile ossifying fibroma: CT and MR findings. Eur Radiol 2002;12(Suppl 3):S109–S113 Urs AB, Kumar P, Arora S, Augustine J. Clinicopathologic and radiologic correlation of ossifying fibroma and juvenile ossifying fibroma—an institutional study of 22 cases. Ann Diagn Pathol 2012;17(2):198–203

Yousem DM, Kraut MA, Chalian AA. Major salivary gland imaging. Radiology 2000;216(1):19–29

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Case 28 Kress B, Griesbeck F, Stippich C, Bähren W, Sartor K. Bell palsy: quantitative analysis of MR imaging data as a method of predicting outcome. Radiology 2004;230(2):504–509 Sartoretti-Schefer S, Kollias S, Wichmann W, Valavanis A. T2-weighted three-dimensional fast spin-echo MR in inflammatory peripheral facial nerve palsy. AJNR Am J Neuroradiol 1998;19(3):491–495

Case 29 Larson TC III, Reese DF, Baker HL Jr, McDonald TJ. Glomus tympanicum chemodectomas: radiographic and clinical characteristics. Radiology 1987;163(3):801–806

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Koeller KK, Alamo L, Adair CF, Smirniotopoulos JG. Congenital cystic masses of the neck: radiologic-pathologic correlation. Radiographics 1999;19(1):121–146 Morón FE, Morriss MC, Jones JJ, Hunter JV. Lumps and bumps on the head in children: use of CT and MR imaging in solving the clinical diagnostic dilemma. Radiographics 2004;24(6):1655–1674

Case 38 Grindler D, Cannady S, Batra PS. Computed tomography findings in sinonasal Wegener’s granulomatosis. Am J Rhinol Allergy 2009;23(5):497–501 Lohrmann C, Uhl M, Warnatz K, Kotter E, Ghanem N, Langer M. Sinonasal computed tomography in patients with Wegener’s granulomatosis. J Comput Assist Tomogr 2006;30(1):122–125

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Kaneda T, Minami M, Ozawa K, et al. MR of the submandibular gland: normal and pathologic states. AJNR Am J Neuroradiol 1996;17(8): 1575–1581 Munir N, Bradley PJ. Diagnosis and management of neoplastic lesions of the submandibular triangle. Oral Oncol 2008;44(3):251–260

Case 40 Mills R. Cholesteatoma behind an intact tympanic membrane in adult life: congenital or acquired? J Laryngol Otol 2009;123(5):488–491 Watts S, Flood LM, Clifford K. A systematic approach to interpretation of computed tomography scans prior to surgery of middle ear cholesteatoma. J Laryngol Otol 2000;114(4):248–253

Case 41 Brandwein MS, Som PM. Inflammatory diseases. In: Curtin HD, Som PM. Head and Neck Imaging. 4th ed. St. Louis, MO: Mosby, Inc.; 2003: 193–259 Yousem DM, Fellows DW, Kennedy DW, Bolger WE, Kashima H, Zinreich SJ. Inverted papilloma: evaluation with MR imaging. Radiology 1992;185(2):501–505

Case 42 Earwaker J. Paranasal sinus osteomas: a review of 46 cases. Skeletal Radiol 1993;22(6):417–423 Eller R, Sillers M. Common fibro-osseous lesions of the paranasal sinuses. Otolaryngol Clin N Am 2006;39(3):585–600, x Erdogan N, Demir U, Songu M, Ozenler NK, Uluç E, Dirim B. A prospective study of paranasal sinus osteomas in 1,889 cases: changing patterns of localization. Laryngoscope 2009;119(12):2355–2359

Case 43 Mahmood MF. Orbit: embryology, anatomy, and pathology. In: Curtin HD, Som PM. Head and Neck Imaging. 4th ed. St. Louis, MO: Mosby, Inc.; 2003:529–654

Case 44 Lee CH, Hur DG, Roh HJ, et al. Survival rates of sinonasal squamous cell carcinoma with the new AJCC staging system. Arch Otolaryngol Head Neck Surg 2007;133(2):131–134 Loevner LA, Sonners AI. Imaging of neoplasms of the paranasal sinuses. Neuroimaging Clin N Am 2004;14(4):625–646 Russell JO, Hoschar AP, Scharpf J. Papillary squamous cell carcinoma of the head and neck: a clinicopathologic series. Am J Otolaryngol 2011;32(6):557–563

Case 49 Bonneville F, Savatovsky J, Chiras J. Imaging of cerebellopontine angle lesions: an update. Part 1: enhancing extra-axial lesions. Eur Radiol 2007;17(10):2472–2482

Case 50 Shah GV, Wong KK, Gandhi D, Parmar H, Mukherji SK. Squamous cell carcinoma: initial diagnosis and staging with PET/CT. PET Clin 2008;2(4):469–480 Som PM, Curtin HD, Mancus AA. Imaging-based nodal classification for evaluation of neck metastatic adenopathy. AJR Am J Roentgenol 2000;174(3):837–844

Case 51 Bloom DC, Carvalho DS, Dory C, Brewster DF, Wickersham JK, Kearns DB. Imaging and surgical approach of nasal dermoids. Int J Pediatr Otorhinolaryngol 2002;62(2):111–122 Hedlund G. Congenital frontonasal masses: developmental anatomy, malformations, and MR imaging. Pediatr Radiol 2006;36(7):647–662 Martin-Fiori E, Holzmann D, Huisman TAGM, Kellenberger CJ, Schneider JFL, Willi UV. Developmental Nasal Midline Masses in Children: Neuroradiological Evaluation. Berlin, Germany: Springer Verlag; 2003

Case 52 Rai S, Sodhi SP, Sandhu SV. Pleomorphic adenoma of submandibular gland: An uncommon occurrence. Natl J Maxillofac Surg 2011;2(1):66–68 Ziglinas P, Arnold A, Arnold M, Zbären P. Primary tumors of the submandibular glands: a retrospective study based on 41 cases. Oral Oncol 2010;46(4):287–291

Case 53 Bonneville F, Savatovsky J, Chiras J. Imaging of cerebellopontine angle lesions: an update. Part 2: intra-axial lesions, skull base lesions that may invade the CPA region, and non-enhancing extra-axial lesions. Eur Radiol 2007;17(11):2908–2920 Lanzino G, Dumont AS, Lopes MB, Laws ER Jr. Skull base chordomas: overview of disease, management options, and outcome. Neurosurg Focus 2001;10(3):E12

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van den Berg R. Imaging and management of head and neck paragangliomas. Eur Radiol 2005;15(7):1310–1318

Shah GV. MR imaging of salivary glands. Neuroimaging Clin N Am 2004;14(4):777–808 Tonami H, Ogawa Y, Matoba M, et al. MR sialography in patients with Sjögren syndrome. AJNR Am J Neuroradiol 1998;19(7):1199–1203

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Case 55

Corey AS, Hudgins PA. Radiographic imaging of human papillomavirus related carcinomas of the oropharynx. Head Neck Pathol 2012;6(Suppl 1): S25–S40 Sigal R, Zagdanski AM, Schwaab G, et al. CT and MR imaging of squamous cell carcinoma of the tongue and floor of the mouth. Radiographics 1996;16(4):787–810

Gallanos M, Hafner JW. Posttraumatic internal jugular vein thrombosis presenting as a painful neck mass in a child. Pediatr Emerg Care 2008;24(8):542–545 Nakamura S, Sadoshima S, Doi Y, et al. Internal jugular vein thrombosis, Lemierre’s syndrome; oropharyngeal infection with antibiotic and anticoagulation therapy—a case report. Angiology 2000;51(2):173–177

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Case 56

Folmer RL, McMenomey SO, Shiley SG. Tinnitus and hyperacusis. In: Cummings CW, Haughey BH, Thomas JR, Harker LA, Flint PW, eds. Otolaryngology: Head & Neck Surgery, 4th ed. St. Louis, MO: Mosby, Inc.; 2005:2832–2847

Friedman AD, Burns JA, Lutch MJ, Zeitels SM. Submucosal neoplasms of the laryngeal introitus. J Laryngol Otol 2012;126(7):706–713 Ganly I, Patel SG, Matsuo J, et al. Predictors of outcome for advanced-stage supraglottic laryngeal cancer. Head Neck 2009;31(11):1489–1495

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Further Readings Kim JW, Yoon SY, Park IS, Park SW, Kim YM. Correlation between radiological images and pathological results in supraglottic cancer. J Laryngol Otol 2008;122(11):1224–1229

Case 57 Vertinsky AT, Schwartz NE, Fischbein NJ, Rosenberg J, Albers GW, Zaharchuk G. Comparison of multidetector CT angiography and MR imaging of cervical artery dissection. AJNR Am J Neuroradiol 2008;29(9):1753–1760

Case 58 Banko B, Dukić V, Milovanović J, Kovač JD, Artiko V, Maksimović R. Diagnostic significance of magnetic resonance imaging in preoperative evaluation of patients with laryngeal tumors. Eur Arch Otorhinolaryngol 2011;268(11):1617–1623 Beitler JJ, Muller S, Grist WJ, et al. Prognostic accuracy of computed tomography findings for patients with laryngeal cancer undergoing laryngectomy. J Clin Oncol 2010;28(14):2318–2322

Case 59 Chung EM, Smirniotopoulos JG, Specht CS, Schroeder JW, Cube R. From the archives of the AFIP: Pediatric orbit tumors and tumorlike lesions: nonosseous lesions of the extraocular orbit. Radiographics 2007;27(6):1777–1799

Case 60 Friedman ER, John SD. Imaging of pediatric neck masses. Radiol Clin N Am 2011;49(4):617–632, v Huoh KC, Durr ML, Meyer AK, Rosbe KW. Comparison of imaging modalities in pediatric thyroglossal duct cysts. Laryngoscope 2012;122(6):1405–1408

Case 61 Curtin HD, Som PM. Parapharyngeal and masticator space lesions. In: Curtin HD, Som PM, eds. Head and Neck Imaging. 4th ed. St. Louis, MO: Mosby, Inc.; 2003:1954–2003

Case 62 Dutt SN, Mirza S, Chavda SV, Irving RM. Radiologic differentiation of intracranial epidermoids from arachnoid cysts. Otol Neurotol 2002;23(1):84–92 Mafee MF, Kumar A, Heffner DK. Epidermoid cyst (cholesteatoma) and cholesterol granuloma of the temporal bone and epidermoid cysts affecting the brain. Neuroimaging Clin N Am 1994;4(3):561–578 Phillips GS, LoGerfo SE, Richardson ML, Anzai Y. Interactive Web-based learning module on CT of the temporal bone: anatomy and pathology. Radiographics 2012;32(3):E85–E105

Case 63 Bilaniuk LT, Savino PJ, Zimmerman RA. Visual pathways. In: Curtin HD, Som PM, eds. Head and Neck Imaging. 4th ed. St. Louis, MO: Mosby, Inc.; 2003:735–781

Case 64 Gilbert K, Dalley RW, Maronian N, Anzai Y. Staging of laryngeal cancer using 64-channel multidetector row CT: comparison of standard neck CT with dedicated breath-maneuver laryngeal CT. AJNR Am J Neuroradiol 2010;31(2):251–256 Hu Q, Luo F, Zhu SY, Zhang Z, Mao YP, Hui Guan X. Staging of laryngeal carcinoma: comparison of high-frequency sonography and contrastenhanced computed tomography. Clin Radiol 2012;67(2):140–147

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Case 65 Bauman NM, Khanna G, Nerad J, Sato Y, Smith RJH. Causes of facial swelling in pediatric patients: correlation of clinical and radiologic findings. Radiographics 2006;26:157–171 Brandwein MS, Som PM. Salivary glands: anatomy and pathology. In: Curtin HD, Som PM, eds. Head and Neck Imaging. 4th ed. St. Louis, MO: Mosby, Inc.; 2003:2005–2133

Case 66 Chin SC, Rice H, Som PM. Spread of goiters outside the thyroid bed: a review of 190 cases and an analysis of the incidence of the various extensions. Arch Otolaryngol Head Neck Surg 2003;129(11):1198–1202 Pollard DB, Weber CW, Hudgins PA. Preoperative imaging of thyroid goiter: how imaging technique can influence anatomic appearance and create a potential for inaccurate interpretation. AJNR Am J Neuroradiol 2005;26(5):1215–1217

Case 67 Koeller KK, Alamo L, Adair CF, Smirniotopoulos JG. Congenital cystic masses of the neck: radiologic-pathologic correlation. Radiographics 1999;19(1):121–146

Case 68 Bradley PJ. Adenoid cystic carcinoma of the head and neck: a review. Curr Opin Otolaryngol Head Neck Surg 2004;12(2):127–132 Christe A, Waldherr C, Hallett R, Zbaeren P, Thoeny H. MR imaging of parotid tumors: typical lesion characteristics in MR imaging improve discrimination between benign and malignant disease. AJNR Am J Neuroradiol 2011;32(7):1202–1207

Case 69 Khanna G, Sato Y, Smith RJ, Bauman NM, Nerad J. Causes of facial swelling in pediatric patients: correlation of clinical and radiologic findings. Radiographics 2006;26(1):157–171 Yonetsu K, Izumi M, Nakamura T. Deep facial infections of odontogenic origin: CT assessment of pathways of space involvement. AJNR Am J Neuroradiol 1998;19(1):123–128

Case 70 Bron LP, Traynor SJ, McNeil EB, O’Brien CJ. Primary and metastatic cancer of the parotid: comparison of clinical behavior in 232 cases. Laryngoscope 2003;113(6):1070–1075 Hinerman RW, Indelicato DJ, Amdur RJ, et al. Cutaneous squamous cell carcinoma metastatic to parotid-area lymph nodes. Laryngoscope 2008;118(11):1989–1996

Case 71 Chung EM, Specht CS, Schroeder JW. From the archives of the AFIP: pediatric orbit tumors and tumorlike lesions: neuroepithelial lesions of the ocular globe and optic nerve. Radiographics 2007;27(4): 1159–1186

Case 72 Lee YY, Wong KT, King AD, Ahuja AT. Imaging of salivary gland tumours. Eur J Radiol 2008;66(3):419–436 Vaidya AD, Pantvaidya GH, Metgudmath R, Kane SV, D’Cruz AK. Minor salivary gland tumors of the oral cavity: a case series with review of literature. J Cancer Res Ther 2012;8(Suppl 1):S111–S115

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Case 73 Azouz EM, Saigal G, Rodriguez MM, Podda A. Langerhans’ cell histiocytosis: pathology, imaging and treatment of skeletal involvement. Pediatr Radiol 2005;35(2):103–115 Hoover KB, Rosenthal DI, Mankin H. Langerhans cell histiocytosis. Skeletal Radiol 2007;36(2):95–104

Case 74 Amin MF, El Ameen NF. Diagnostic efficiency of multidetector computed tomography versus magnetic resonance imaging in differentiation of head and neck paragangliomas from other mimicking vascular lesions: comparison with histopathologic examination. Eur Arch Otorhinolaryngol 2013;270(3):1045–1053 Wieneke JA, Smith A. Paraganglioma: carotid body tumor. Head Neck Pathol 2009;3(4):303–306

Case 75 Ueno T, Tanaka YO, Nagata M, et al. Spectrum of germ cell tumors: from head to toe. Radiographics 2004;24(2):387–404

Case 76 Bergmark RW, Guo DP, Lin HW, Faquin WC, Young GS, Saxon KG. Vagal schwannoma. Ear Nose Throat J 2011;90(9):410–411 Saito DM, Glastonbury CM, El-Sayed IH, Eisele DW. Parapharyngeal space schwannomas: preoperative imaging determination of the nerve of origin. Arch Otolaryngol Head Neck Surg 2007;133(7):662–667 Shirakura S, Tsunoda A, Akita K, et al. Parapharyngeal space tumors: anatomical and image analysis findings. Auris Nasus Larynx 2010;37(5):621–625

Case 77 Nemzek WR, Swartz JD. Temporal bone: inflammatory disease. In: Curtin HD, Som PM, eds. Head and Neck Imaging. 4th ed. St. Louis, MO: Mosby, Inc.; 2003:1173–1229

Case 78 Aiken AH. Imaging of thyroid cancer. Semin Ultrasound CT MR 2012;33(2):138–149 Hoang JK, Lee WK, Lee M, Johnson D, Farrell S. US Features of thyroid malignancy: pearls and pitfalls. Radiographics 2007;27(3):847–860, discussion 861–865 Kim DW, Eun CK, In HS, Kim MH, Jung SJ, Bae SK. Sonographic differentiation of asymptomatic diffuse thyroid disease from normal thyroid: a prospective study. AJNR Am J Neuroradiol 2010;31(10):1956–1960

Case 79 Aribandi M, McCoy VA, Bazan C III. Imaging features of invasive and noninvasive fungal sinusitis: a review. Radiographics 2007;27(5):1283–1296 Cestari DM, Metson RB, Cunnane ME, Faquin WC. Case records of the Massachusetts General Hospital. Case 40-2008. A 26-year-old man with blurred vision. N Engl J Med 2008;359(26):2825–2833

Case 80 Ben Salem D, Duvillard C, Assous D, Ballester M, Krausé D, Ricolfi F. Imaging of nasopharyngeal cysts and bursae. Eur Radiol 2006;16(10): 2249–2258 Moody MW, Chi DH, Mason JC, Phillips CD, Gross CW, Schlosser RJ. Tornwaldt’s cyst: incidence and a case report. Ear Nose Throat J 2007;86(1):45–47, 52

Case 81 Koplewitz BZ, Springer C, Slasky BS, et al. CT of hemangiomas of the upper airways in children. AJR Am J Roentgenol 2005;184(2):663–670

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Vilanova JC, Barceló J, Smirniotopoulos JG, et al. Hemangioma from head to toe: MR imaging with pathologic correlation. Radiographics 2004;24(2):367–385

Case 82 Becker M, Burkhardt K, Dulguerov P, Allal A. Imaging of the larynx and hypopharynx. Eur J Radiol 2008;66(3):460–479 Hermans R. Staging of laryngeal and hypopharyngeal cancer: value of imaging studies. Eur Radiol 2006;16(11):2386–2400 Keberle M, Kenn W, Hahn D. Current concepts in imaging of laryngeal and hypopharyngeal cancer. Eur Radiol 2002;12(7):1672–1683

Case 83 Mukherji SK. Pharynx. In: Curtin HD, Som PM, eds. Head and Neck Imaging. 4th ed. St. Louis, MO: Mosby, Inc.; 2003:1465–1520

Case 84 Branstetter BF IV, Weissman JL. Infection of the facial area, oral cavity, oropharynx, and retropharynx. Neuroimaging Clin N Am 2003;13(3):393– 410, ix La’porte SJ, Juttla JK, Lingam RK. Imaging the floor of the mouth and the sublingual space. Radiographics 2011;31(5):1215–1230

Case 85 Maeda M, Kato H, Sakuma H, Maier SE, Takeda K. Usefulness of the apparent diffusion coefficient in line scan diffusion-weighted imaging for distinguishing between squamous cell carcinomas and malignant lymphomas of the head and neck. AJNR Am J Neuroradiol 2005;26(5):1186–1192

Case 86 Mukherji SK. Pharynx. In: Curtin HD, Som PM, eds. Head and Neck Imaging. 4th ed. St. Louis, MO: Mosby, Inc.; 2003:1465–1520 Sinno H, Thibaudeau S, Coughlin R, Chitte S, Williams B. Management of infantile parotid gland hemangiomas: a 40-year experience. Plast Reconstr Surg 2010;125(1):265–273 Weiss I, O TM, Lipari BA, Meyer L, Berenstein A, Waner M. Current treatment of parotid hemangiomas. Laryngoscope 2011;121(8):1642–1650

Case 87 Mukherji SK. Pharynx. In: Curtin HD, Som PM, eds. Head and Neck Imaging. 4th ed. St. Louis, MO: Mosby, Inc.; 2003:1465–1520

Case 88 Guldfred LA, Philipsen BB, Siim C. Branchial cleft anomalies: accuracy of pre-operative diagnosis, clinical presentation and management. J Laryngol Otol 2012;126(6):598–604 Triglia JM, Nicollas R, Ducroz V, Koltai PJ, Garabedian EN. First branchial cleft anomalies: a study of 39 cases and a review of the literature. Arch Otolaryngol Head Neck Surg 1998;124(3):291–295

Case 89 King AD, Lei KI, Ahuja AT. MRI of primary non-Hodgkin’s lymphoma of the palatine tonsil. Br J Radiol 2001;74(879):226–229

Case 90 Ahmadi J, North CM, Segall HD, Zee CS, Weiss MH. Cavernous sinus invasion by pituitary adenomas. AJR Am J Roentgenol 1986;146(2):257–262 Molitch ME, Cowen L, Stadiem R, Uihlein A, Naidich M, Russell E. Tumors invading the cavernous sinus that cause internal carotid artery compression are rarely pituitary adenomas. Pituitary 2012;15(4):598–600

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Further Readings Zhang Y, He N, Zhou J, Chen Y. The relationship between MRI invasive features and expression of EMMPRIN, galectin-3, and microvessel density in pituitary adenoma. Clin Imaging 2011;35(3):165–173

Case 91 Belden CJ, Mancuso AA, Kotzur IM. The developing anterior skull base: CT appearance from birth to 2 years of age. AJNR Am J Neuroradiol 1997;18(5):811–818

Case 92 Bloch OG, Jian BJ, Yang I, et al. Cranial chondrosarcoma and recurrence. Skull Base 2010;20(3):149–156 Cho YH, Kim JH, Khang SK, Lee JK, Kim CJ. Chordomas and chondrosarcomas of the skull base: comparative analysis of clinical results in 30 patients. Neurosurg Rev 2008;31(1):35–43 Hong P, Taylor SM, Trites JR, Bullock M, Nasser JG, Hart RD. Chondrosarcoma of the head and neck: report of 11 cases and literature review. J Otolaryngol Head Neck Surg 2009;38(2):279–285

Case 93 Slovis TL, Renfro B, Watts FB, Kuhns LR, Belenky W, Spoylar J. Choanal atresia: precise CT evaluation. Radiology 1985;155(2):345–348

Case 94 Ishman SL, Friedland DR. Temporal bone fractures: traditional classification and clinical relevance. Laryngoscope 2004;114(10):1734–1741 Saraiya PV, Aygun N. Temporal bone fractures. Emerg Radiol 2009;16(4):255–265 Swartz JD. Temporal bone trauma. Semin Ultrasound CT MR 2001;22(3):219–228

Case 95 Brandwein MS, Som PM. Salivary glands: anatomy and pathology. In: Curtin HD, Som PM, eds. Head and Neck Imaging. 4th ed. St. Louis, MO: Mosby, Inc.; 2003:2005–2133

Further_readings.indd 206

Case 96 Potter BO, Sturgis EM. Sarcomas of the head and neck. Surg Oncol Clin N Am 2003;12(2):379–417 Razek AA, Huang BY. Soft tissue tumors of the head and neck: imaging-based review of the WHO classification. Radiographics 2011;31(7):1923–1954

Case 97 Joseffer SS, Cooper PR. Modern imaging of spinal tuberculosis. J Neurosurg Spine 2005;2(2):145–150 Ludwig B, Lazarus AA. Musculoskeletal tuberculosis. Dis Mon 2007;53(1):39–45

Case 98 Goel A, Kothari M. Cavernous sinus meningiomas. J Neurosurg 2010;113(5):1085 Razek AA, Castillo M. Imaging lesions of the cavernous sinus. AJNR Am J Neuroradiol 2009;30(3):444–452

Case 99 Tailor TD, Gupta D, Dalley RW, Keene CD, Anzai Y. Orbital neoplasms in adults: clinical, radiologic, and pathologic review. RadioGraphics 2013;33:1739–1758 von Holstein SL. Tumours of the lacrimal gland. Epidemiological, clinical and genetic characteristics. Acta Ophthalmol 2013;91:1–28

Case 100 Dauer EH, Lewis JE, Rohlinger AL, Weaver AL, Olsen KD. Sinonasal melanoma: a clinicopathologic review of 61 cases. Otolaryngol Head Neck Surg 2008;138(3):347–352 Turri-Zanoni M, Medicina D, Lombardi D, et al. Sinonasal mucosal melanoma: molecular profile and therapeutic implications from a series of 32 cases. Head Neck 2013;35(8):1066–1077

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Index Locators refer to case number. Locators in boldface indicate primary diagnosis.

A

Aberrant internal carotid artery, 29 Abscess, 13 masticator space, 69 periodontal, 84 peritonsillar, 83 prevertebral, 17 retropharyngeal, 17 root canal, 84 sublingual space, 84 subperiosteal, 1, 23 tonsillar, 83 Acoustic schwannoma, 32 Acute otomastoiditis, 14 Acute sinusitis, 18 Adenocystic carcinoma of larynx, 58 of parotid gland, 68 Adenoidal hyperplasia, 80 Adenoid cystic carcinoma lacrimal gland, 99 of larynx, 56 of minor salivary gland, 82 Adenoma follicular, 66, 78 pituitary macroadenoma, 90, 98 pleomorphic, 61, 99 Adenopathy, 87 lymphadenopathy, 45 Adrenal pheochromocytoma, 74 Allergic fungal sinusitis, 79 Angina, Ludwig’s, 84 Angiosarcoma, scalp, 70 Anterior cephalocele, 91 Anterior neck malignant necrotic node, 60 Anticoagulation, 57 Antrochoanal polyp, 24 Arachnoid cyst, 39, 62 Arteriovenous malformation, 81 Arteritis large vessel, 57 Takayasu, 57 Atherosclerotic disease, 57 Atresia, choanal, 93

B

Bacterial osteodiskitis, 97 Basal cell carcinoma, 25 BCC. See Branchial cleft cyst Beam hardening artifacts, 84 Bell’s palsy, 28

Wesoloski_Index.indd 207

Benign lymphoepithelial cysts (BLC), 54, 95 Benign lymphoepithelial lesions, of parotid gland, 70 Benign mixed tumor of parotid gland, 68 of salivary gland, 72 of submandibular gland, 48, 52 Bilateral Warthin tumors, 95 BLC. See Benign lymphoepithelial cysts Bone fracture, temporal, 94 Bone tumor, primary, 73 Branchial apparatus, 67 Branchial cleft cyst (BCC), 19, 33, 37 first, 88 infected, 88 second, 50, 65, 67 Breathing, difficulty in, 100 Brown tumors of hyperparathyroidism, 25

C

Capillary hemangioma, 86 orbital, 16, 59 Carotid artery thrombosis, 55 Carotid body paraganglioma, 74 Carotid body tumor, 45 Carotid-cavernous fistula, 20 Carotid space schwannoma, 74 vagal, 76 Cavernous hemangioma, 98 of orbit, 16 Cavernous sinus fistula, 11 Cavernous sinus meningioma, 90, 98 Cavernous sinus schwannoma, 98 Cellulitis postseptal, 1 preseptal, 1 Cephalocele, 80 anterior, 91 Cerebellopontine angle lesions, 35 Cerebellopontine angle meningioma, 35, 49 Cervical artery dissection, 57 Cervical esophageal carcinoma, 82 Cervical spondylodiskitis, 17 CHARGE, 93 Cherubism, 25 Choanal atresia, 93 Cholesteatoma congenital, 12, 14, 22, 62 in middle ear, 29 pars tensa, 40 petrous apex, 12, 14, 26, 62

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208

Index

Cholesterol granuloma of middle ear, 40 petrous apex, 4, 12, 14, 26, 62 Chondrosarcoma, 21, 53, 96 of larynx, 58, 64 of skull base, 92 Chordoma, clival, 53, 92 Choriocarcinomas, 75 Chronic otitis media, with granulation, 40 Chronic otomastoiditis, 14 Chronic parotitis, 54 Chronic sinusitis, 18, 38 Chronic sore throat, 82 Clival chordoma, 53, 92 Coats disease, 15 Cocaine abuse, 38 Cochlear aplasia, 34 Cochlear dysplasia, 34 Cochlear otosclerosis, 30 Colloid cyst, 66 Common carotid artery thrombosis, 55 Congenital choanal atresia, 93 Congenital cholesteatoma, 22 petrous apex, 12, 14, 62 Congenital enlarged vestibular aqueduct, 35 Congenital hemangioma, 86 Congenital sensorineural hearing loss, 34 Cranial nerve VI palsy, 14, 92 Cranial nerve V palsy, 14 Craniopharyngioma, 31, 53, 63 CSF leak, 91 Cutaneous scalp angiosarcoma, 70 Cystic hygroma, 65, 67, 81, 83, 88 Cystic meningioma, 39 Cystic vestibular dysplasia, 34

D

Dehiscent jugular bulb, 6, 8 Demyelinating optic neuritis, 5 Dental amalgam, 84 Dermoids nasal, 51 orbital, 23 of tongue, 60 Developmental delay, 31 Devic disease, 5 Diabetes insipidus, 75 Differentiated thyroid carcinoma, 78 Diplopia, monocular, 20 Discoloration, 81 Diving ranulas, 65 Dizziness, 39 Dysphagia, 58, 80

E

Ear cholesteatoma in, 29 cholesterol granuloma of, 40

Wesoloski_Index.indd 208

Ear pain, 22 EBV infection, 87 EG. See Eosinophilic granuloma ELST. See Endolymphatic sac tumor Encephalocele, 91 Endolymphatic sac tumor (ELST), 4, 35 Enlarged vestibular aqueduct, 35 Eosinophilic granuloma (EG), 73 Epidermoid cyst, 39 of sublingual space, 84 Epidermoid lesions, cerebellopontine angle, 35 Epiglottis, squamous cell carcinoma of, 56 Epistaxis, 9, 100 Esophageal carcinoma, cervical, 82 Esthesioneuroblastoma, 2, 100 Ethmoidal lesions, 91 Ewing sarcoma, 96 Extranodal lymphoma, 89

F

Facial asymmetry, 7 Facial deformity, 25 Facial nerve normal enhancement, 28 palsy of, 4, 22, 28 Facial nerve hemangioma, 22, 28 Facial nerve schwannoma, 22, 32 Facial pressure, 38 Facial swelling, 38, 67, 81 Falx calcifications, 25 FDG, 70 Fibrosarcoma, 96 Fibrous dysplasia, 7, 30, 36, 42 First branchial cleft cyst, 88 Fistula carotid-cavernous, 20 cavernous sinus, 11 Follicular adenoma, 66 of thyroid gland, 78 Fracture, temporal bone, 94 Fungal sinusitis, 18, 44 allergic, 79

G

Gardner syndrome, 96 GCT. See Germ cell tumor Germ cell tumor (GCT), 63, 75 Germinomas, 75 Glioma. See also Paraganglioma optic nerve, 5, 71 Glomus jugulare paraganglioma, 4, 6, 8, 10 Glomus tympanicum (GT), 29 Glomus vagale paraganglioma, 74, 76 Glottic laryngeal squamous cell carcinoma, 64 Goiter, multinodal, 66 Gorlin syndrome, 25 Gradenigo syndrome, 14 Granuloma

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209

Index

cholesterol of middle ear, 40 petrous apex, 4, 12, 14, 26, 62 eosinophilic, 73 of larynx, 64 Wegener granulomatosis, 11, 38, 64 Graves disease, 11, 20 GT. See Glomus tympanicum

H

Jugular foramen schwannoma, 6, 8, 10 Jugular schwannoma, 45 Jugular vein thrombosis, 55 Jugulotympanicum paraganglioma, 4 Juvenile nasopharyngeal angiofibroma (JNA), 9, 41

K

Kyphosis, 97

L

Infantile hemangioma, 81 of parotid gland, 86 Infected first branchial cleft cyst, 88 Inflammatory pseudotumor, 99 Inherited retinoblastoma, 96 Inspissated secretions, 79 Intralabyrinthine schwannoma, 32 Intraparotid lymph node, suppurative, 88 Intravestibular schwannoma, with acoustic schwannoma within IAC, 32 Invasive squamous cell carcinoma, 96 Inverted papilloma, 9, 18, 24, 41

Labyrinthitis, 32 Labyrinthitis ossificans (LO), 77 Lacrimal gland lymphoma, 3, 99 Lacrimal gland pleomorphic adenoma, 99 Langerhans cell histiocytosis, 73 Large vessel arteritis, 57 Laryngocele, 56 Larynx adenocystic carcinoma of, 56 adenoid cystic carcinoma of, 58 chondrosarcoma of, 58, 64 granuloma of, 64 Wegener granulomatosis of, 64 Lazy eye syndrome, 36 Left ICA dissection, 57 Li-Fraumeni syndrome, 96 Lingual tonsil squamous cell carcinoma, 46 LO. See Labyrinthitis ossificans Longitudinal temporal bone fracture, 94 Ludwig’s angina, 84 Lyme disease, 5 Lymphadenopathy, 45 Lymphangioma, orbital, 59 Lymphatic malformation, 88 of orbit, 16 Lymph nodes necrotic, 19, 37, 55, 67 parotid gland, 70 reactive, 76 suppurative, 83 suppurative intraparotid, 88 Lymphoid lesions, 3 Lymphoma, 13, 49, 85 extranodal, 89 Hodgkin, 13, 85, 89 lacrimal gland, 3, 99 myositis/myopathy from, 11 non-Hodgkin, 13, 38, 44, 50, 85, 89 as ONG mimic, 71 sinonasal, 2, 100 tonsillar, 89 Lymphoproliferative disease, 20 of lacrimal gland, 99 Lymphoproliferative lesions of orbit, 20 Lytic bony lesions, 73

J

M

Headache, 6 Hearing loss, 6, 8, 22 mixed conductive, 30 sensorineural, 26, 30, 32 congenital, 34 high frequency, 10 progressive, 4, 35 Hemangioma capillary, 16, 59, 86 cavernous, 16, 98 congenital, 86 facial nerve, 22, 28 infantile, 81, 86 orbital, 43 capillary, 16, 59 cavernous, 16 parotid gland, 86 sella/parasellar, 90 Hematoma, 17 masticator space, 69 Hemifacial spasm, 22 Hemorrhagic colloid cyst, 78 Hemotympanum, 93, 94 High riding jugular bulb, 6, 8 HIV, 5, 95 Hodgkin lymphoma, 13, 85, 89 Horner syndrome, 76 Hydrocephalus, 75 Hygroma. See Cystic hygroma Hyperparathyroidism, 25 Hypopharynx, squamous cell carcinoma of, 82

I

JNA. See Juvenile nasopharyngeal angiofibroma Jugular foramen meningioma, 6, 8, 10

Wesoloski_Index.indd 209

Macroadenoma, pituitary, 90, 98 Malignant lesion of petrous apex, 14

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210

Index

Malignant sinonasal masses, 24 Mandibular metastatic deposit, 96 Masses parotid, 68 sinonasal, 2, 18, 24, 38 Masticator space abscess, 69 hematoma, 69 sarcoma, 96 venolymphatic malformation, 96 McCune-Albright syndrome, 7 Medulloblastoma, 25 Melanoma metastatic disease, 70 sinonasal, 100 Ménière disease, 32 Meningioma cavernous sinus, 90, 98 cerebellopontine angle, 35, 49 cystic, 39 jugular foramen, 6, 8, 10 olfactory, 2 orbital, 43 skull base, 92 Meningitis, 77, 91 MEN type II syndrome, 74 Metastatic disease, 85 in adenoids, 87 in diabetes insipidus, 75 facial asymmetry from, 7 kyphosis from, 97 laryngeal structures and, 21 as lytic bony lesions, 73 mandibular deposits, 96 melanoma, 70 myositis/myopathy from, 11 neuroblastoma, 7 nodal, of parotid gland, 70 osteosarcoma, 7 schwannoma resembling, 6 squamous cell carcinoma, 70 Middle ear cholesteatoma in, 29 cholesterol granuloma of, 40 Minor salivary gland, adenoid cystic carcinoma of, 82 Minor salivary gland carcinoma of tongue, 72 Mixed conductive hearing loss, 30 Mixed temporal bone fracture, 94 Monocular diplopia, 20 Mucin, 79 Mucocele of petrous apex, 12 sinonasal, 18 submandibular gland, 52 Mucoepidermoid carcinoma, of parotid gland, 68 Multinodal goiter, 66 Multiple odontogenic keratocysts (Gorlin syndrome), 25

Wesoloski_Index.indd 210

Multiple sclerosis, 5 Musculoskeletal tuberculosis, 97 Myeloma, 87

N

Nasal cavity squamous cell carcinoma, 100 Nasal dermoid, 51 Nasal obstruction, 38, 41, 100 right-sided, 24 Nasogastric tube, 93 Nasopharyngeal carcinoma (NPC), 85, 87 Necrotic lymph node, 19, 37, 55, 67 Necrotic node of delphian chain, 60 Neuroblastoma esthesioneuroblastoma, 2, 100 metastatic, 7 Neurofibromatosis type I (NF1), 71, 86 Neurofibromatosis type II (NF2), 10, 32, 98 Neuromyelitis optica, 5 NF1. See Neurofibromatosis type I NF2. See Neurofibromatosis type II NHL. See Non-Hodgkin lymphoma Nodal metastatic disease of parotid gland, 70 Nodal squamous cell carcinoma, 50 Non-Hodgkin lymphoma (NHL), 13, 38, 44, 50, 85, 89 Nonobstructive sialadenitis, 27 Normal enhancement of facial nerve, 28 NPC. See Nasopharyngeal carcinoma

O

Obstructive sialadenitis, 27 Ocular pressure, 38 Odontogenic keratocysts, 25 Olfactory meningioma, 2 ONG. See Optic nerve glioma Optic nerve glioma (ONG), 5, 71 Optic neuritis, 71 demyelinating, 5 Oral tongue squamous cell carcinoma, 46 Orbital capillary hemangioma, 16, 59 Orbital cellulitis, 20 Orbital dermoid, 23 Orbital hemangioma, 43 Orbital lymphangioma, 59 Orbital meningioma, 43 Orbital phlegmon, 59 Orbital postseptal cellulitis, 1 Orbital proptosis, 1 Orbital pseudotumor, 1, 11, 20 Orbital rhabdomyosarcoma, 1 Orbital schwannoma, 43 Orbital tumor, 23 Ossifying fibroma, 36, 42 Osteodiskitis bacterial, 97 pyogenic, 97 Osteogenesis imperfect, 30

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Index

Osteosarcoma, 42, 96 metastatic, 7 Otalgia, 76 Otitis media, 26 chronic, 40 Otomastoiditis, 14 Otosclerosis, cochlear, 30 Otospongiosis, 77

P

Paget disease, 7, 30, 77 Palsies cranial nerve V, 14 cranial nerve VI, 14, 92 facial nerve, 4, 22, 28 right facial nerve, 4 Papillary thyroid carcinoma, metastatic deposits, 4 Papilloma, inverted, 9, 18, 24, 41 Paraganglioma carotid body, 74 carotid body tumor, 45 glomus jugulare, 4, 6, 8, 10 glomus vagale, 74, 76 GT, 29 jugulotympanicum, 4 Paranasal sinus blood, 79 Paranasal sinus osteoma, 42 Parapharyngeal space schwannoma, 61 Parasellar hemangioma, 90 Parinaud syndrome, 75 Parotid gland adenocystic carcinoma of, 68 benign lymphoepithelial lesions of, 70 benign mixed tumor of, 68 infantile hemangioma of, 86 lymph nodes, 70 mucoepidermoid carcinoma of, 68 nodal metastatic disease of, 70 right, 54 Warthin tumor of, 68 Parotid mass, 68 Parotitis, chronic, 54 Pars tensa cholesteatoma, 40 Partial laryngectomy, 56 Perineural spread of skull base mass, 28 Periodontal abscess, 84 Periorbital cellulitis, preseptal, 1 Periorbital pain, 98 Peritonsillar abscess, 83 Persistent hyperplastic primary vitreous, 15 Petrous apex cholesteatoma, 12, 14, 26 Petrous apex cholesterol granuloma, 4, 12, 14, 26, 62 Petrous apex congenital cholesteatoma, 12, 14, 62 Petrous apex fluid collection, 12 Petrous apicitis, 14, 26

Wesoloski_Index.indd 211

PHACE syndrome, 81, 86 Pharyngitis retropharyngeal lymph node suppuration in, 17 tonsillar/peritonsillar abscess and, 83 Phlegmon, orbital, 59 Photophobia, 38 Pituitary apoplexy, 31 Pituitary macroadenoma, 98 with cavernous sinus invasion, 90 Plasmacytoma, 92 Pleomorphic adenoma, 61 of lacrimal gland, 99 Plexiform neurofibroma, 86 Postseptal cellulitis, orbital, 1 Preauricular swelling, 88 Preseptal periorbital cellulitis, 1 Prevertebral abscess, 17 Primary bone tumor, 73 Progressive sensorineural hearing loss, 4, 35 Proptosis painful, 20 right orbital, 1 right-sided, 16, 20 Pseudoaneurysm, 57 Pulsatile tinnitus, 4, 6, 29, 47 Pyogenic osteodiskitis, 97

Q

Quadrilateral retinoblastoma, 75

R

Ranula, 65 diving, 65 simple, 65, 84 Rathke’s cleft cyst (RCC), 31, 63 Rb. See Retinoblastoma RCC. See Rathke’s cleft cyst Reactive effusion, 17 Reactive lymph nodes, 76 Renal cell carcinoma, metastatic deposits, 4 Respiratory tract infection, 88 Retinoblastoma (Rb), 15 inherited, 96 quadrilateral, 75 Retro-orbital pain, 14 Retropharyngeal abscess, 17 Retropharyngeal internal/common carotid arteries, 47 Rhabdomyosarcoma, 69, 96 Rheumatoid arthritis, 54 Rhinitis, 79 Right facial nerve palsy, 4 Right orbital proptosis, 1 Right parotid gland, 54 Right-sided nasal obstruction, 24 Right-sided proptosis, 16, 20 Root canal abscess, 84

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Index

S

Salivary gland carcinoma adenoid cystic, 82 minor, 72 Salivary gland tumor, 3, 61, 89 benign mixed, 72 Sarcoidosis, 11, 20, 38 Sarcoma angiosarcoma, 70 chondrosarcoma, 21, 53, 58, 64, 92, 96 Ewing, 96 fibrosarcoma, 96 masticator space, 96 osteosarcoma, 7, 42, 96 rhabdomyosarcoma, 69, 96 synovial, 96 SATCHMO mnemonic, 31, 63 Scalp angiosarcoma, 70 SCCA. See Squamous cell carcinoma Schwannoma, 49 acoustic, 32 carotid space, 74, 76 cavernous sinus, 98 facial nerve, 22, 32 intralabyrinthine, 32 intravestibular, 32 jugular, 45 jugular foramen, 6, 8, 10 orbital, 43 parapharyngeal space, 61 vagal, of carotid space, 76 vestibular, 10, 22 Schwannoma of jugular foramen, 4 Sebaceous cyst, 51 Second branchial cleft cyst, 50, 65, 67 Seizures, 91 Sella/parasellar hemangioma, 90 Seminomas, 75 Sensorineural hearing loss, 26, 30, 32 congenital, 34 high frequency, 10 progressive, 4, 35 Seroma, 17 Sialadenitis nonobstructive, 27 obstructive, 27 submandibular, 84 submandibular gland, 48, 52 Sialoliths, 27 Simple ranulas, 65, 84 Sinonasal lymphoma, 2, 100 Sinonasal mass, 2, 18, 38 malignant, 24 Sinonasal melanoma, 100 Sinonasal mucocele, 18 Sinonasal neoplasm, 18 Sinonasal osteoma, 36

Wesoloski_Index.indd 212

Sinonasal polyp, 41 Sinonasal polyposis, 18, 24 Sinonasal squamous cell carcinoma, 2, 24, 44 Sinonasal undifferentiated carcinoma, 2 Sinuses cavernous fistula, 11 meningioma, 90, 98 schwannoma, 98 expansion of, 79 Sinusitis acute, 18 allergic, 79 chronic, 18, 38 fungal, 18, 44, 79 inverted papilloma and, 24 Sistrunk procedure, 33, 60 Sjögren syndrome, 3, 54, 70, 95 Skull base chondrosarcoma, 92 Skull base mass, perineural spread of, 28 Skull base meningioma, 92 SLE, 54 Sore throat, chronic, 82 Spinal tuberculosis, 97 Squamous cell carcinoma (SCCA), 9, 21 of distal Wharton’s duct, 27 of epiglottis, 56 glottic laryngeal, 64 of hypopharynx, 82 invasive, 96 of lingual tonsil, 46 metastatic disease, 70 nasal cavity, 100 nodal, 50 sinonasal, 2, 24, 44 subglottic, 58 supraglottic, 56 of tongue, 46, 72 of tonsils, 89 Subglottic squamous cell carcinoma, 58 Sublingual space abscess, 84 Sublingual space epidermoid cyst, 84 Submandibular gland benign mixed tumor, 48, 52 Submandibular gland carcinoma, 48 Submandibular gland mucocele, 52 Submandibular gland sialadenitis, 48, 52 Submandibular sialadenitis, 84 Subperiosteal abscess, 1, 23 Suppurative adenitis, as malignancy mimic, 50 Suppurative intraparotid lymph node, 88 Suppurative lymph node, 83 Supraglottic squamous cell carcinoma of epiglottis, 56 Synovial sarcoma, 96

T

Takayasu arteritis, 57 TB. See Tuberculosis

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213

Index

Thrombosis carotid artery, 55 jugular vein, 55 Thyroglossal duct cyst (TDC), 33, 60 Thyroid carcinoma differentiated, 78 papillary, 4 Thyroidectomy, 78 Thyroid gland, follicular adenoma of, 78 Thyroid ophthalmopathy, 20 Thyroid orbitopathy (Graves disease), 11 Tinnitus, 32 pulsatile, 4, 6, 29, 47 Tongue dermoids of, 60 minor salivary gland carcinoma of, 72 squamous cell carcinoma of, 72 venous malformation of, 46 Tonsillar abscess, 83 Tonsillar enlargement, 95 Tonsillar lymphoma, 89 Tonsillectomy, 83 Tonsils, squamous cell carcinoma of, 89 Tornwaldt’s cyst, 80 Total parotidectomy, 70 Transverse temporal bone fracture, 94 Trapped fluid of petrous apex, 14, 26, 62 Tuberculosis (TB), 5 musculoskeletal, 97 spinal, 97

Wesoloski_Index.indd 213

U

Unilateral sensorineural hearing loss, 62

V

Vagal schwannoma of carotid space, 76 Vascular malformation, of orbit, 16 Vasculitis, 57 Venolymphatic malformation (VLM), 13, 19, 33, 37, 51 masticator space, 96 of orbit, 16 Venous malformation, 86 of tongue, 46 Venous varix of orbit, 16 Vertigo, 32 Vestibular dysplasia, cystic, 34 Vestibular schwannoma, 10, 22 VHL. See von Hippel-Lindau disease VLM. See Venolymphatic malformation von Hippel-Lindau disease (VHL), 4, 74

W

Warthin tumor bilateral, 95 of parotid gland, 68 Wegener granulomatosis, 11, 38 of larynx, 64 Wharton’s duct calculus with obstructive sialadenitis, 27

Y

Yolk sac tumors, 75

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