Case 31: What is the most likely diagnosis?
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Case 31: What is the most likely diagnosis?
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Persistent Stapedial Artery feeding Middle Meningeal Artery
Case 31: What is the most likely diagnosis?
A rare finding, the persistent stapedial artery (PSA) is typically found incidentally and almost never is symptomatic. It can occur with an aberrant ICA or in isolation. The SA arises as a branch of the embryonic hyoid artery (persists as caroticotympanic a.) and divides into dorsal branch (future mid mening a.) and ventral branch (future max and mandib aa.) it then typically regresses by the 3 rd fetal month. On CT it is seen as a vessel arising from the internal carotid artery at the vert/horiz petrous junction, entering the hypotympanum and traveling along the coch promontory. It enters the obturator foramen of the stapes. From there it travels along an enlarged tympanic segment of the facial nerve canal. Foramen spinosum is absent (blue arrows – right absent, normal left) because the persistent stapedial artery becomes the middle meningeal artery by entering the tympanic cavity through the facial hiatus.
DDx: Persistent Stapedial Artery feeding Middle Meningeal Artery 1. 2. 3.
Paraganglioma Aberrant ICA Laterally deviated ICA
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DDx
Case 32: What is the most likely diagnosis?
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External Auditory Canal Atresia- Ossicular Fusion
Case 32: What is the most likely diagnosis?
Congenital atresia of the external auditory canal is caused by a failure of canalization of the epithelial plug portion of the first branchial arch. It can occur syndromically or nonsyndromically. Persistence of the tympanic ring results in a bony atresia plate at the level of the tympanic membrane (red arrows). Ossicular malformations may be seen as they arise from the first branchial cartilage. Diagnosis is usually made at birth. Further CT assessment should include: ossicle development, presence of cholesteatoma, possibility of middle ear fluid, mastoid development, and facial nerve location.
DDx: External Auditory Canal Atresia 1. 2. 3. 4.
Cleft Lip and Palate Crouzon Syndrome Microtia Osteogenesis Imperfecta
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DDx
Left Vestibular and Lateral Semicircular Canal Dysplasia
Case 33: What is the most likely diagnosis?
Malformations of the inner ear are present in about 20% of cases with congenital sensorineural hearing loss. Dysplasia of the inner ear may be inherited, sporadic, or the result of chromosomal aberrations and results from an arrest of maturation during one of the stages of inner ear embryogenesis. The lateral semicircular canal is the inner ear structure most frequently found to be malformed due to its late stage of formation. SSC abnormalities can occur with anomalies of the vestibule and cochlea or in isolation with the latter felt to be related to a molecular/genetic etiology and the former arrested development. It may be sporadic or syndromic as well, with the latter showing more severe changes.
DDx: Left Vestibular and LSC Dysplasia 1. 2. 3. 4.
Goldenhar’s Syndrome Waardenburg Syndrome Alagille’s Syndrome CHARGE syndrome
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DDx
Dehiscent Superior Semicircular Canal
Case 34: What is the most likely diagnosis?
Superior semicircular canal dehiscence syndrome is a condition in which vestibular symptoms are elicited by sound or pressure. When the bone over the canal becomes thin or dehiscent, it acts as an additional window for the vestibular system, allowing pressure and noise changes to induce vestibular activity. Patients often present with symptoms of sound- or pressure-induced dizziness or chronic imbalance. Some patients may hear a swishing sound when they move their eyes in a certain direction. Dehiscent superior SC is most often caused by postnatal failure of bone formation over the SC (red arrows), likely due to a malpositioned primitive otocyst. If this otocyst lies too close to the developing brain, the migratory patterns of the loose reticular cells are altered. These mesenchymal cells are thought to be necessary for normal labyrinth development. Trauma has also been posited as a possible etiology.
Right
Left
DDx: Dehiscent Superior Semicircular Canal 1. 2. 3. 4.
Benign Paroxysmal Positional Vertigo Inner Ear Meniere Disease Inner Ear Perilymphatic Fistula Labyrinthitis
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DDx
Mild Cochlear Dysplasia- Right Cochlear Aperture Narrowing Case 35: What is the likely diagnosis? Suggesting CNmost 8 Hypoplasia Cochlear nerve deficiency as a cause of SNHL is not uncommon. MRI is useful for evaluating the presence of neural elements. There are 3 categories of cochlear nerve deficiency type1: total absence, type 2a: absent or hypoplastic nerve, labyrinthine dysplasia, and Type 2b: absent/hypoplastic nerve with normal labyrinth. Af Cochlear Implant unctional auditory nerve is necessary for cochlear implant. IACCandidate abnormalities may be associated with hypoplasia or aplasia of the vestibulocochlear nerve with resultant sensorineural hearing loss. Patients with IAC dysplasia or duplication are likely candidates for cochlear implantation. Stenosis or occlusion of the cochlear aperture (red arrow) is highly associated with deficiency of the cochlear nerve and should be scrutinized in all preoperative evaluations.
DDx: Cochlear Aperture Stenosis 1. 2. 3.
Paget’s Disease Otosclerosis Fibrous Dysplasia
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DDx
Case 36: What is the most likely diagnosis?
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Bilateral Dysplasia Case 36a: What isCochlear the most likely diagnosis? Cochlear dysplasias are part of a spectrum of abnormalities of the bony and membranous labyrinth. Abnormalities are classified decreasing in severity from Michel deformity (complete labyrinthine aplasia), cochleovestibular aplasia, common cavity IP-1 (cystic cochleovestibular malformation), cochleovestibular hypoplasia, and IP-2 (incomplete partition type 2, classic Mondini malformation). The type of deformity relates to time of developmental arrest, ranging from the 3 rd to the 7th week of gestation. IP2 deformity is limited to the mid and apical turns of the cochlea where ther is an absent modiolus and ISS. The cochlea is limited to 1.5 turns. The basal turn is normal. Hearing loss is widely variable. The VA is always large in these patients.
DDx: Cochlear Dysplasia 1. 2.
Incomplete partition type 2 (Mondini Dysplasia) LVAS
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DDx
Case 37: What is the most likely diagnosis?
Right
Left 1 of 2
Large Vestibular Aqueduct Syndrome
Case 37: What is the most likely diagnosis?
LVAS is the most common abnormality of the inner ear in children with sensorineural and fluctuating hearing loss. Large vestibular aqueduct syndrome is described as a vestibular aqueduct (VA) measuring more than 1.5mm in diameter (red arrows) at the midpoint. Cochlear and modiolar abnormalities are not uncommon. Treatment in the form of hearing aids and cochlear implants is essential as patients with hearing impairment in the prelingual period suffer from speech disturbance. Cause of SNHL is not well understood, but two main theories. First, Reflux of hyperosmolar proteins from the ELS into the cochlea duct with subsequent osmotic damage to the neuroepithelium. Second, Modiolar deficiency results in CSF pressure waves damaging hair cells.
DDx: Large Vestibular Aqueduct Syndrome 1. 2. 3. 4.
Pendred Syndrome IP-2 Waardenburg Syndrome GJB2 gene mutation
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DDx
Case 38: What is the most likely diagnosis?
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Bilateral Mondini- Sensorineural Hearing Loss
Case 38: What is the most likely diagnosis?
The classic Mondini malformation consisted of a triad of cystic cochlear apex with a normal basal turn, large vestibule with normal SCCs, and a large vestibular aqueduct. This is now more accurately termed incomplete partition type 2 (IP-2). It is a result of arrest of inner ear development during the seventh week of gestation. The development of the Organ of Corti is widely variable with resultant wide range of hearing deficits from none to profound. Hearing loss is fluctuating. Vestibular prominence is variable and typically minimal. The semicircular canals appear normal. The vestibular aqueduct is always enlarged.
DDx: IP-2 1. 2. 3.
Cochleovestibular hypoplasia Pendred Syndrome Large Vestibular Aqueduct Syndrome
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DDx
DDx: Inner Ear Aplasia 1.
Case 39: What is the most likely diagnosis?
Labyrinthitis Ossificans
Inner Ear Aplasia Inner Ear Aplasia, Michel Aplasia, is due to arrested development at gestational week 3. This is prior to formation of the otic vesicle with resultant complete labyrinthine aplasia. There may be complete absence of the inner ear or nondescript dense bone. The middle and external ear are normally intact. Accounts for less than 1% of all congenital inner ear malformations. Can b confused with labyrinthitis ossificans. Although this will typically demonstrate a more normal appearing inner ear bony margin.
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DDx
DDx: Bony Atresia of Round Window 1.
Case 40: What is the most likely diagnosis?
Congenital Stapes Ankylosis
Bony Atresia of Round Window-Maximum Conductive Hearing Loss Round window atresia can be seen in association with syndromal anomalies such as mandibulofacial dysostosis, Mondini type anomalies or cretinism, or with extensive otosclerosis. Non-syndromal round window atresia is extremely rare. Full occlusion of the round window (red arrows) may result in a complete air-bone gap and a surgical procedure to open the window should result in normalizing hearing levels. Patients usually present with conductive or mixed hearing loss. Most cases also present with stapes ankylosis. Embryologically, during normal otic capsule ossification, cartilage in the round window niche prevents ossification of its opening. Often, round window atresia is discovered after unsuccessful stapedectomy.
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DDx