Case 21: What is the most likely diagnosis?
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Case 21: What is the most likely diagnosis?
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Case 21: What is the most likely diagnosis?
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Post-traumatic Post Infectious TMJ and External Auditory Canal Case 21: What is theCyst most likely diagnosis? The external auditory canal and the TMJ are intimately located. Therefore, trauma to the TMJ is known to produce trauma to the external auditory canal. If infection begins in the external auditory canal due to trauma or other mode breaking down the skin/cerumen protective barrier, it can become severe with EAC obstruction of purulent drainage and debris (red arrows). Post-traumatic cysts are those that result from resolution of hematomas. Infection in the cyst makes it tense and painful, and may make the cyst more adherent to surrounding tissues.
DDx: Post-traumatic Post Infectious TMJ and EAC Cyst 1. 2. 3.
Malignant Otitis Externa 1st Branchial cleft cyst Lipoma
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DDx
Case 22: What is the most likely diagnosis?
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Cholesteatoma- Incus Erosion with Adherence to Facial Nerve
Case 22: What is the most likely diagnosis?
Four theories are posited in the etiology of acquired cholesteatoma: retraction, papillary proliferation, immigration, and metaplasia. The retraction pocket theory is the most popular. It suggests that eustachian tube dysfunction results in diminished pressure in the middle ear with subsequent retraction and perforation of the TM. The skin lining the EAC also covers the outersurface of the TM. The skin growing in this region extends laterally. If this migration is blocked keratin debris will accumulate, an encrusted plug forms which expands with moisture, and a cholesteatoma subsequently forms. These can become infected. Hallmark of cholesteatoma is bone, particularly ossicular and scutum, destruction. This case demonstrates soft tissue in the epi- and mesotympanum with erosion of the incus, adherence to the facial nerve canal, and thickened TM (red arrows).
DDx: Cholesteatoma 1. 2. 3. 4. 5.
Cholesterol Granuloma Metastasis Rhabdomyosarcoma Squamous cell Carcinoma Adenoma
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DDx
Case 23: What is the most likely diagnosis?
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Bilateral EAC Stenosis- Congenital Ossicular Fusions
Case 23: What is the most likely diagnosis?
Congenital external auditory canal stenosis is defined as having a diameter of less than 4mm. Embryologically, EAC stenosis occurs as a result of partial failure of canalization. About 48% of children with EAC stenosis develop cholesteatoma, and it should be looked for. Often, ossicular fusion is seen concurrently with EAC stenosis (red arrows), especially in congenital disorders. EAC stenosis ranges from mild to atresia, and ossicular fusion ranges from inter-ossicle fusion to fusion with the walls of the middle ear.
DDx: Congenital EAC Stenosis with Ossicular Fusion 1. Bony or membranous EAC atresia 2. Chronic stenosing otitis externa 3. Keratosis obturans 4. Chronic granulomatous dss.
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DDx
Case 24: What is the most likely diagnosis?
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Case 24: What is the most likely diagnosis?
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Petrous Apex Early Cholesterol Granuloma
Case 24: What is the most likely diagnosis?
Cholesterol granulomas are rare, benign cysts that can occur at the petrous apex. Granulomas often occur throughout the body as a reaction to foreign material. Cholesterol granulomas of the petrous apex are dangerous because of their proximity to the ear and important nerves. Most often, cholesterol granulomas form when the air cells in the petrous apex are obstructed. The obstruction creates a vacuum that causes blood to be drawn into the air cells. As those RBCs are broken down, cholesterol in the hemoglobin is released. The immune system reacts to the cholesterol as a foreign body, producing an inflammatory response. Recurrent hemorrhage makes the mass expand. Patients often present with unilateral hearing loss, tinnitus, facial twitching, vertigo, and facial numbness. On MRI, cholesterol granuloma will appear hyperintense on T1weighted imaging and hyperintense on T2 (red arrows) without appreciable enhancement. Treatment is surgical drainage with permanent aeration reestablished.
DDx: Petrous Apex Cholesterol Granuloma 1.
Cholesteatoma
2.
Mucocele
3.
Hemangioma
4.
Chondrosarcoma
5.
Petrous Apicitis
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DDx
Case 25: What is the most likely diagnosis?
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High Jugular Bulb with a Jugular Diverticulum
Case 25: What is the most likely diagnosis?
Certain vascular variations are a frequent cause of pulsatile tinnitus and possible cause of a vascularappearing tympanic membrane. Jugular variants include high riding, dehiscent, and diverticula. Arterial variants include an aberrant ICA and persistent stapedial artery. The main differential for a vascular appearing retrotympanic mass is vascular variant vs a paraganglioma. A large, high-riding nondehiscent jugular bulb is defined by the most cephalad point of the bulb reaching or rising above the floor of the internal auditory canal (red arrow). This can mimic a lesion, but the bony margins will always be well corticated. When only a fingerlike projection of the jugular bulb projects cephalad (medial and posterior) a jugular bulb diverticulum (blue arrow) diagnosis is made. Pulsatile tinnitus may be present with this venous variant as turbulence of venous flow may occur.
DDx: Dehiscent Jugular Bulb 1.
Paragangliomas
2.
Meningiomas
3.
Schwannomas
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DDx
Case 26: What is the most likely diagnosis?
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Case 26: What is the most likely diagnosis?
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Glomus Jugulare/Jugulotympanicum
Case 26: What is the most likely diagnosis?
A glomus jugulare tumor is a paraganglioma that most commonly arises from the adventitia of the jugular vein. Overall rare, it is the second most common paraganglioma type (carotid body most common). Glomus jugulare may also arise from Jacobson’s nerve or Arnold’s nerve of the jugular bulb as glomus bodies accompany theses nerves as well. Glomus jugulare is seen most commonly in adults 40-60yo, with a moderate female predilection. Significant inner ear involvement produces pulsatile tinnitus and hearing loss and even some cranial nerve palsies. Typical growth extends into the mastoid air cells, middle ear, and eustachian tube (red arrows). CT is the most useful for defining the bony margins of the tumor, which are typically irregularly eroded. Eventually, there may be erosion of the jugular plate, allowing entry into the middle ear (blue arrow) now called a glomus jugulotympanicum. An important distinction to make for the surgeon. CT also assists in assessing the integrity of the ossicles and bony labyrinth. Malignant transformation is uncommon (2-13% of cases).
DDx: Glomus Jugulare 1. 2. 3. 4. 5.
Schwannoma Bony Metastases Meningioma Jugular Bulb Thrombosis Normal Anatomic Variation (asymmetry of jugular bulb size, dehiscent jugular bulb)
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DDx
Case 27: What is the most likely diagnosis?
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Case 27: What is the most likely diagnosis?
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Case 27: What is the most likely diagnosis?
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Temporal Bone Langerhans Cell Histiocytosis in an Adult
Case 27: What is the most likely diagnosis?
The exact etiology of Langerhans cell histiocytosis is unknown. The majority of Langerhans cases occur in children, but presentation in adults is becoming more recognized. Osseous involvement is common for Langerhans as a lytic lesion. Biopsy is often required to make a definitive diagnosis of Langerhan’s (Birbeck granules on the cytoplasmic membrane). The local manifestations of Langerhan’s include aural discharge, localized swelling, vertigo, deafness, cutaneous lesions, and cervical lymphadenopathy. Hearing loss is a rare manifestation most often occurring as an obstruction to the external auditory meatus. The origin of temporal bone lesions is often around the mastoid and spreading anteriorly. On MR, moderate enhancement helps to distinguish this from (red arrows). MR appearance is not specific, however. Early imaging findings may appear similar to inflammatory disease.
DDx: Langerhan’s Cell Histiocytosis of the TB 1. 2. 3. 4. 5.
Wegener’s Cholesteatoma Rhabdomyosarcoma Coalescent Mastoiditis SCCA
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DDx
DDx: Lyme Disease 1. 2. 3. 4. 5.
Case 28: What is the most likely diagnosis?
Metastasis Tuberculosis Syphilis Sarcoidosis Schwannoma
Lyme Disease-Bilateral Cranial Nerve VII Palsy; Right Cranial Nerve IV Palsy Lyme disease is caused by the spirochete Borrelia burgdorferi, transmitted by ixodid ticks. Neurologic symptoms begin in Stage II of disease progression beginning at 1-4mos after initial tick bite. The triad of neurologic manifestations of Lyme disease- meningitis, cranial neuritis, and radiculoneuritis- is characteristic. Facial palsy is common and helps differentiate from other diseases. MR studies usually focus on white matter lesions and demyelination similar to multiple sclerosis. MR often shows meningeal and nerve-root enhancement. The facial nerve is the most commonly involved cranial nerve; palsy may be unilateral or bilateral. Affected segments appear thickened and frequently enhance with contrast (red arrows) .
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DDx
Case 29: What is the most likely diagnosis?
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DDx: Aberrant Internal Carotid Artery 1. 2.
Case 29: What is the most likely diagnosis?
Paraganglioma (Glomus Tympanicum/ jugulotympanicum) Dehiscent Jugular Bulb
Aberrant Internal Carotid Artery An aberrant carotid artery coursing through the middle ear is a rare anomaly typically presenting as pulsatile tinnitus with a vascular retrotympanic mass. The internal carotid normally enters the cranium through the petrous bone by ascending through the vertical segment of the petrous carotid canal. The ascending segment is infra-cochlear in location and is separated laterally from the tympanic cavity by the carotid plate, a bony covering usually less than 0.5mm in thickness. The aberrant carotid artery actually represents an enlarged inferior tympanic artery (Ascending pharyngeal branch) anastomosing with an enlarged caroticotympanic artery (petrous ICA branch) when the cervical segment of the internal carotid artery is underdeveloped or has regressed during embryogenesis. The aberrant carotid enters the tympanic cavity through an enlarged inferior tympanic canaliculus (between the carotid and , courses through under the cochlear promontory anteriorly and the medially and enters the horizontal carotid canal through a dehiscence in the carotid plate (red arrows). On radiologic examination, there is characteristically: 1, absence of vertical carotid canal; 2, enlargement of the inferior tympanic canaliculus; 3, an aberrant course of the artery through the hypotympanum; and 4, DDx 2 of 2 dehiscence of the caortid plate.
Aberrant Internal Carotid Artery-Bx as a Child but Survived
Case 20a: What is the most likely diagnosis?
An aberrant carotid artery coursing through the middle ear is a rare anomaly, producing pulsatile tinnitus. The internal carotid normally enters the cranium through the petrous bone by ascending through the vertical segment of the carotid canal. The ascending segment is infra-cochlear in location and is separated laterally from the tympanic cavity by the carotid plate, a bony covering usually less than 0.5mm in thickness. The aberrant carotid artery is actually an enlarged inferior tympanic artery (ascending pharyngeal branch) anastomosing with an enlarged caroticotympanic artery (petrous ICA branch) when the cervical segment of the internal carotid artery is underdeveloped or has regressed during embryogenesis. The aberrant carotid enters the tympanic cavity through an enlarged inferior tympanic canaliculus, more lateral and posteriorly positioned than normal, courses along the cochlear promontory anteriorly and then medially enters the horizontal carotid canal through a dehiscence in the carotid plate (red arrows). On radiologic examination, there is characteristically: 1. absence of vertical carotid canal, 2. enlargement of the inferior tympanic canaliculus, 3. an aberrant course of the artery through the hypotympanum, and 4. dehiscence of the caortid plate.
DDx: Aberrant Internal Carotid Artery 1. 2. 3. 4.
Laterally displaced ICA Glomus Tympanicum Dehiscent Jugular Bulb Persistent stapedial srtery
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DDx
Dehiscent Jugular Bulb- Vein
Case 30: What is the most likely diagnosis?
A dehiscent jugular vein lacks a complete cortical covering. As a result, the jugular vein bulges into the middle ear from below through the absence of the sigmoid plate normally lying between the middle ear cavity and the jugular foramen. It is most commonly seen at the posteroinferior quadrant of the TM. The jugular bulb is a structure that is normally the dilated portion of the upper jugular vein, at the junction between the sigmoid sinus and the jugular vein. It is sometimes impossible to differentiate venous anomalies clinically, so identifying the osseous anatomy on thin-section bone CT helps make the diagnosis. CT is useful for showing the jugular vein bulging into the middle ear through a discontinuity in the cortex of the jugular fossa (red arrows). Patients often present with hearing loss or tinnitus.
DDx: Dehiscent Jugular Bulb-Vein 1. 2. 3. 4.
Glomus Jugulotympanicum Aberrant Internal Carotid Artery Asymmetric Jugular Bulb High-Riding Jugular Bulb
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DDx