Challenge Cases

Case 151

History: adult with skeletal deformity. Legend: B) The line to assess for basilar invagination courses from the hard palate to the undersurface of the occiput or to the posterior margin of the foramen magnum (B). The dens should be less than 5 mm above this line. Note the segmentation anomalies, kyphoscoliosis, and foramen magnum stenosis. Differential diagnosis of causes of platybasia and basilar invagination: Paget’s disease, rheumatoid arthritis, osteogenesis imperfecta, osteomalacia, Klippel- Feil syndrome.

Case 152

History: young adult with hearing loss after treatment for same. Legend: Axial high resolution CT scan of the temporal bone shows a focus of demineralization (long arrow). The stapes prosthesis (short arrow) does not have its piston set in the vestibule and was not transmitting sound well. Differential diagnosis: otosyphilis, osteogenesis imperfecta, otospongiosis.

Case 153

History: child with trismus, pain. Legend: Axial CT scan reveals a soft tissue mass (arrows) associated with lysis of the left mandible. Differential diagnosis: Ewing’s sarcoma, Langerhans’ cell histiocytosis, neuroblastoma, lymphoma/leukemia, metastasis.

Case 154 NO IMAGES AVAILABLE. History: elderly man with solid, painful right-sided neck mass. Differential diagnosis: soft tissue sarcoma, muscular lymphoma, hemangiopericytoma, malignant fibrous histiocytoma.

Case 155

History: young adult with facial discomfort, skin rash and mild proptosis. Legend: A) Note the thickening of the greater wing of the sphenoid (arrow) with minimal soft tissue causing left lateral rectus muscle displacement. The bone shows periosteal reaction extending to the lateral orbital wall. Differential diagnosis: osteomyelitis, Ewing’s sarcoma, osteosarcoma, histiocytosis, SAPHO syndrome.

Case 156

History: middle-aged man presenting with nasal obstruction and right divergent strabism. Legends: C) Axial T2WI shows an isointense well defined lesion (arrow) occupying the right anterior ethmoid cells and extending to the medial wall of the right orbit. D) Axial T1WI shows the homogeneous bright signal of this lesion (arrow). Differential diagnosis: soft tissue rhabdomyosarcoma, synovial sarcoma, chondrosarcoma, myositis ossificans.

Case 157

History: middle-aged woman with paresthesias and weakness in the right arm. Legends: The bony protuberance (arrow) on the axial (A) and coronal (B) images may represent either a cervical rib from C7 or an enlarged transverse process. Either of these may lead to brachial plexopathy and/or thoracic outlet syndrome. Differential diagnosis: fibrous bands, cervical rib, fracture and callous, apophysomegaly.

Case 158 NO IMAGES AVAILABLE. History: japanese young adult with palpable neck mass. Differential diagnosis: Kikuchi’s disease, Kawasaki’s disease, Castleman’s disease, metastatic lymphadenopathy, amyloidosis, Kimura’s disease, Rosai Dorfman disease, lymphoma, papillary carcinoma of the thyroid gland, HIV adenopathy.

Case 159 NO IMAGES AVAILABLE. History: post-op child with facial dysmorphism. Differential diagnosis: mandibular hypoplasia, Forrest Gump, Pierre Robin syndrome, Treacher Collins syndrome.

Case 160

History: young adult with bilateral weakness in the intrinsic hand muscles. Legends: A, B) Bilateral enlargement and enhancement of the lower cervical nerve roots as they exit the foramina is present (arrows). Differential diagnosis: neurofibromatosis, chronic inflammatory demyelinating neuropathy (CIPD), multiple schwannomas, Guillain-Barré syndrome, mononeuritis multiplex, Dejerine-Sottas Disease, Charcot-Marie-Tooth disease.

Case 161 NO IMAGES AVAILABLE. History: elderly man with palpable painful neck mass. Differential diagnosis: malignant fibrous histiocytoma, nodular fasciitis, fibrosarcoma, lymphoma.

Case 162

History: teenager with limitation of movement in the neck, torticollis. Legends: A- D) Whether the head is in neutral (A), head turned to the right (B), head turned to the left (C) or coronal neutral position (D), the distance from the dens to the left C1 anterolateral arch (arrow) is widened compared to the right side. This indicates fixed rotatory subluxation. Differential diagnosis: traumatic etiology, Grisel inflammatory etiology, normal variation.

Case 163

History: middle-aged obese woman with headaches, visual blurring. Legends: A, B) T2-weighted scans show reversed cupping of the optic nerve head insertion on the posterior globes, deforming the smooth contour of the rounded sphere. Differential diagnosis: papillitis, pseudopapilledema, patulous optic nerve sheath complexes, papilledema, optic nerve head drusen.

Case 164 NO IMAGES AVAILABLE. History: young adult with bilateral cervical adenopathy, parotid enlargement. Differential diagnosis: lymphoma, sarcoidosis, mastocytosis, amyloidosis, mononucleosis, sinus histiocytosis with massive lymphadenopathy (Rosai- Dorfman).

Case 165

History: middle-aged woman with difficulty breathing, stridor. Legend: A) Moderate thickening of the walls of the trachea is evident on this axial post-contrast CT scan. Differential diagnosis: infections (TB, papillomatosis, croup, histoplasmosis), neoplasms (lymphoma, squamous cell carcinoma, minor salivary gland lesions), metabolic/ acquired (amyloidosis, asthma, tracheopathia osteochondroplastica), radiation, post-operative granulation, Wegener’s granulomatosis, sarcoidosis.

Case 166

History: young adult with sound-induced vertigo. Legends: Oblique coronal (A) and sagittal (B) images show absence of the bone (arrow) overlying the superior semicircular canal. Differential diagnosis of causes of bone dehiscence: post-operative change, meningocele, trauma, congenital/idiopathic, cholesteatoma, chronic otitis media.

Case 167

History: voice change in a young man. Legends: B) Axial T2-weighted scan shows a bright lesion in the supraglottic region with a focal low intensity area within it (arrow). C) This lesion avidly enhances on post gad axial T1 scan and the signal of the focal area within the lesion remains dark (arrow). Differential diagnosis: venous vascular malformation with phleboliths, chondroid lesion, amyloidoma and post-traumatic dystrophic calcification.

Case 168

History: teenager with conductive hearing loss and a blue mass seen on otoscopy. Legends: A, B) Axial CT scans through the temporal bone show a non-erosive mass (arrow) infiltrating the right middle ear cavity. This was said to be blue in color on otoscopy. Parts of the ossicles are engulfed by the mass. C) The coronal CT scan confirms that the mass (arrow) seems to conform to existing constraints of the epi and hemotympanum rather than aggressively eroding bone. Differential diagnosis: cholesteatoma, epidermoid, glial choristoma, schwannoma, hemangioma.

Case169

History: young adult with right-sided hearing loss. Past history of meningitis. Legends: A-D) Axial high resolution CT scans through the temporal bone show foci of increased density/ossification (black arrows) within the “lumen” of the right cochlea. Differential diagnosis: meningitis, perilymphatic fistula, labyrinthitis ossificans, post-traumatic hemolabyrinth.

Case 170

History: young adult after renal transplant with tonsillar pain. Legend: A) A right parapharyngeal non-enhancing mass (arrows) is seen posteromedial to the medial pterygoid muscle. The mass causes deformity of the right palatine tonsil. Differential diagnosis: pleomorphic adenoma, schwannoma, lymphoma, sarcoma, abscess, posttransplant lymphoproliferative disorder.

Case 171

History: elderly woman with left facial pain, twitching. Legends: A) The axial raw data image shows a vessel (arrow) in close proximity to the root entry zone of the left trigeminal nerve. By virtue of the size and course this appeared to be a vein. B) The coronal scan post contrast confirms the apposition of the vessel (arrow) to the fifth cranial nerve. Differential diagnosis: vascular compression may be by the superior cerebellar artery > anterior inferior cerebellar artery > both arteries > veins > basilar artery.

Case 172 NO IMAGES AVAILABLE. History: teenager with neck pain. Differential diagnosis: lymphoma, rhabdomyosarcoma, metastasis, plasmacytoma, Langerhans’ cell histiocytosis.

Case 173

History: history of resection for papillary carcinoma of the thyroid gland with I-131 adjuvant therapy. Legends: A) Note the minimally enhancing soft tissue anterior to the carotid sheath on the right side (long arrow) and in the tracheoesophageal groove (short arrow). Disease in the latter location may affect the recurrent laryngeal nerve. The relative absence of enhancement may reflect the absence of “functioning” tissue since degree of enhancement of the thyroid gland and its function often correlate. B) The mass extends inferiorly to encase the inominate artery on the right (arrow). Differential diagnosis: radiation fibrosis, granulation tissue, reactive thymus, recurrent papillary carcinoma of the thyroid gland.

Case 174 NO IMAGES AVAILABLE. History: young adult with toothache. Differential diagnosis: periapical cyst, dentigerous cyst, adenomatoid odontogenic tumor, ameloblastoma, myxoma.

Case 175 NO IMAGES AVAILABLE. History: young adult with facial fullness and pain. Differential diagnosis: lymphoma, olfactory neuroblastoma, small cell neuroendocrine tumor, inverted papilloma, aggressive fungal sinusitis, squamous cell carcinoma, adenocarcinoma, sinusitis complication.

Case 176

History: middle-aged woman with acute sensorineural right-sided hearing loss. Legends: A) Postcontrast T1-weighted scan suggests an enhancing mass in the right cochlea (arrow). B) Whoooaaa Nelly! Stop right there! This “enhancement” high signal was present on this non-enhanced T1-weighted image implying the presence of blood, fat, melanin, or hyperproteinaceous material. Differential diagnosis: hemolabyrinth, barotrauma, lipoma of labyrinth, pantopaque accumulation, melanoma.

Case 177

History: middle-aged woman with twitching left side of the face. Legends: A) The T2-weighted scan shows a markedly tortuous flow void curving to the internal auditory canal on the left side. B) The enhancing vessel (white arrow) compresses the seventh cranial nerve (black arrow). Differential diagnosis: compression from the anterior inferior cerebellar artery, vertebral artery, and the posterior inferior cerebellar artery, arteriovenous malformation with draining veins, aneurysms.

Case 178

History: middle-aged woman with hormonal abnormalities. Legends: A) The arrow marks a mass in the sella-suprasellar region. > 90% of the time this will be a pituitary adenoma. B) The fact that this lesion (arrow) is extrapituitary is suggested by its distinctness from the native pituitary tissue (p), suggesting a lesion of the stalk. Nonetheless, despite this, a pituitary adenoma should be considered based on the high prevalence of suprasellar growth of adenomas. Differential diagnosis: pituitary adenoma, metastasis, germinoma, Langerhans’ cell histiocytosis, sarcoidosis, subarachnoid seeding, Erdheim-Chester disease, meningioma of diaphragma sella.

Case 179

History: young adult with bilateral sensorineural hearing loss. Legend: Axial post-contrast T1-weighted MR shows bilateral enhancement of the vestibule and lateral semicircular canals (thick arrows). The right cochlea (thin arrow) is also enhancing avidly. Differential diagnosis: hemolabyrinth (if bright pre-gad), viral/bacterial labyrinthitis, subarachnoid seeding, barotraumas inflammation, perilymphatic fistula with inflammation, bilateral labyrinthine schwannomas, autoimmune inner ear disease.

Case 180

History: young adult with short stature, increased head circumference. Legend: Note the frontal bossing and foramen magnum stenosis. Often there is cervical spinal stenosis as well. The sella may be small in size. The optic nerves may course more vertically than usual. Macrocephaly is usually present. Differential diagnosis: mucopolysaccharidoses, achondroplasia.

Case 181

History: teenager with palpable neck mass. Legend: This cystic lesion (arrows) is situated anterior to the carotid sheath, posterior to anterior jugular veins and is separate from the posteromedial thyroid gland. Once identified as separate from the thyroid gland, the differential diagnosis would include the correct diagnosis. Differential diagnosis: thyroid cyst, thyroglossal duct cyst, epidermoid/dermoid, lymphatic malformation, thymic cyst, external fluid-filled laryngocele/pharyngocele, esophageal cyst-diverticulum.

Case 182 NO IMAGES AVAILABLE. History: middle-aged adult with longstanding enophthalmos. Differential diagnosis: post-traumatic deformity, post-operative deformity, maxillary sinus hypoplasia, silent sinus syndrome.

Case 183

History: young adult with palpable mass in the left lower neck. Legend: Large enhancing lymph node (N) in the supraclavicular region is present. The node enhances as much as the thyroid gland. Differential diagnosis: metastatic thyroid carcinoma, Kaposi’s sarcoma, lymphoma, hemangioma/venous vascular malformation, Castleman’s disease, schwannoma, paraganglioma.

Case 184 NO IMAGES AVAILABLE. History: middle-aged woman with facial pain. Differential diagnosis: abscess, malignant fibrous histiocytoma, lymphoma, bone lesion from pterygoid plate (giant cell tumor, osteoblastoma, aneurysmal bone cyst).

Case 185 NO IMAGES AVAILABLE. History: elderly man with skull base pain. Differential diagnosis: (hemorrhagic) metastasis, glomus tumor, endolymphatic sac tumor, epidermoid/dermoid.

Case 186

History: infant with difficulty breathing. Legends: A) Axial CT scan shows narrowing of the opening to the nares (arrows). The right side is worse than the left with evidence of medial maxillary wall thickening bilaterally. B) The cartilaginous narrowing is more apparent on the frontal 3D reconstruction where the waist of the narrowing (arrows) is demarcated. C) Note the absence of a patent airway on the left side compared with right (arrows) just at the bony opening to the nose. Differential diagnosis: choanal atresia, nasal piriform aperture stenosis, masses blocking the nasal airway, hypoplasia of the sinonasal cavity.

Case 187

History: middle-aged woman with hearing loss, headaches. Legends: A) Bilateral benign appearing erosive remodeling of the petrous apices is seen (arrows). Note the scalloped appearance. On the left side this approaches the internal auditory canal. C) The post contrast T1-weighted images show that the signal intensity of the lesions (arrows) is that of CSF with an absence of enhancement. Communication with the subarachnoid space is suggested. Differential diagnosis: Meckel’s cave meningocele, arachnoid cyst, epidermoid.

Case 188 NO IMAGES AVAILABLE. History: young adult with intense chest and neck pain after emesis. Differential diagnosis: pneumomediastinum/thorax tracking upward, post-operative air, necrotizing fasciitis, mucosal tear from trauma to airway, perforated esophagus, gas forming organism infection.

Case 189

History: young female with drainage from a site in the left periparotid region. Legends: A) The arrow shows a small intraparotid cyst on the T2-weighted scan. B, C and D) From the top (B) to the bottom (D) one can see a peripherally enhancing fistula (arrows) leading to the external auditory canal (B) from the body of the parotid gland (D). These scans are fat-suppressed post contrast T1-weighted images.

Differential diagnosis: actinomycosis, first branchial cleft fistula, post traumatic fistula, dermal sinus tract.

Case 190 NO IMAGES AVAILABLE. History: child with facial dysmorphism. Differential diagnosis: hemangioma/venous vascular malformation, neurofibromatosis, Proteus syndrome, Friedreich disease, Beckwith-Wiedemann syndrome/Wilms tumor, Solomon syndrome, Klippel-Trénaunay Weber syndrome.

Case 191 NO IMAGES AVAILABLE. History: child with nasal obstruction. Differential diagnosis: cephalocele, inverted papilloma, hemangioma, nasal glioma, olfactory neuroblastoma, adenocarcinoma, squamous cell carcinoma.

Case 192 NO IMAGES AVAILABLE. History: elderly man with history of treated laryngeal carcinoma. Differential diagnosis: recurrent cancer, effects of radiation therapy, normal post-operative appearance of the larynx.

Case 193 NO IMAGES AVAILABLE. History: middle-aged woman with dry mouth. Differential diagnosis: Sjögren’s syndrome, sarcoidosis, HIV- related benign lymphoepithelial lesions, lymphoma, cat scratch fever, tuberculosis, amyloidosis, Rosai-Dorfman syndrome.

Case 194

History: child with craniofacial dysmorphism, partially treated. Legend: B) This child has undergone strip cranioplasty with widening of the coronal, sagittal, and lambdoid sutures (arrows) for craniosynostosis. The multiple craniosynostosis, small face (white arrow), hypoplastic receding maxilla (white arrowhead) are indicative of syndromic craniostenosis. Differential diagnosis: Crouzon’s syndrome, Carpenter’s syndrome, Pfeiffer’s syndrome, acrocephalosyndactylys I-IV.

Case 195

History: young adult with mixed sensorineural hearing loss bilaterally. Legends: A, B) These CT images show rarefied luscent bone (arrows) just anterior to the oval window and posterior to the cochlea. Differential diagnosis: osteogenesis imperfecta, otosyphilis, otospongiosis, lytic Paget’s disease.

Case 196

History: elderly woman with facial pain, sinusitis. Legend: Multiple lytic lesions (arrows) are seen along the walls of both maxillary antra, associated in many cases with small soft tissue nodules. Differential diagnosis: multiple metastases, Langerhans’ cell histiocytosis, mastocytosis, fungal infection, multiple myeloma.

Case 197

History: middle-aged man with skull base pain and headache. Legends: A) Axial CT scan reveals small hyperdensities (arrows) within the longus colli-capitus muscle complex anterior to the vertebral body. B) The MR shows the high signal intensity inflammation associated with the tendinitis. The inflammation (arrows) shown on this T2-weighted image far exceeds the extent of the calcification. Differential diagnosis: myositis ossificans, tumoral calcinosis, calcific tendinitis, dystrophic calcification associated with metabolic diseases.

Case 198

History: young adult with painless slow-growing mass in her posterior left neck Legends: A) This mass (arrows) has intermediate signal intensity between that of fat and muscle in the subcutaneous tissue of the posterior neck on the T1-weighted sagittal scan. B) On the T2-weighted scan the lesion (arrows) is very bright in signal, a characteristic that generally suggests a more benign neoplastic or inflammatory process. C) Its multilobulated nature is also appreciated on the axial T1 weighted scan where it does not appear to have infiltrative margins.

Differential diagnosis: lipoma, liposarcoma, myxoid liposarcoma, hibernoma, nodular fasciitis, resolving hematoma, abscess, seroma, lymphangioma, venous vascular malformation, lymphoma, hemangiosarcoma.

Case 199

History: middle-aged adult with protruding facial mass. Legends: A) A bubbly bone lesion emanates from the anterior right maxilla with benign expansion of the maxillary walls (arrows). The lesion does not appear to be associated with a tooth on this axial CT image. E) The value of this gadolinium-enhanced T1-weighted fat suppressed scan is identifying a solid enhancement pattern (arrow) which implies that this is not an odontogenic or congenital cyst. A neoplasm must be considered. Differential diagnosis: minor salivary gland neoplasms (pleomorphic adenoma, adenoid cystic carcinoma), fibrous dysplasia, ameloblastoma, synovial sarcoma, odontogenic myxoma, chondromyxoid fibroma, sarcoma, giant cell granuloma, other fibro-osseous lesions.

Case 200

History: child with craniofacial dysmorphism. Legend: B) 3D reconstruction of the axial CT data reveals depression of the orbital floor (short arrow) and left lateral maxillary hypoplasia (long arrow). The left half of the face appears to sag, representing hemifacial atrophy. Differential diagnosis: Parry- Romberg syndrome, amniotic band syndrome, Sturge- Weber syndrome, hemifacial microsomia of Padwa, Dyke- Davidoff- Masson syndrome, Goldenhar syndrome, scleroderma (saber slash).