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Left-Sided Hearing Loss
This case focuses on a patient presenting with left-sided hearing loss, ultimately diagnosed as fenestral otosclerosis (FOto) — a common cause of conductive hearing loss in adults.
Imaging Overview:
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Axial and coronal NECT scans of the temporal bones demonstrate:
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Normal right side
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On the left side, a lytic focus anterior to the oval window, localized at the fissula ante fenestram
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This lucent lesion represents early otospongiosis, where normal dense bone is replaced with spongy bone.
Clinical Insight:
Fenestral otosclerosis is a form of primary bone dysplasia that affects the otic capsule, particularly near the oval window. This causes stapes fixation, impeding sound transmission. Audiometry may reveal a conductive hearing loss with air-bone gap. If untreated, it may advance to the cochlear (sensorineural) form.
Case courtesy of Remy Lobo, MD
University of Michigan, University of Utah