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63-Year-Old Man with Progressive Hearing Loss Since Age 13
This case features a 63-year-old man presenting with progressive bilateral hearing loss since childhood, ultimately diagnosed with bilateral cavitary otosclerosis.
Imaging overview:
Axial temporal bone CT of the right and left sides demonstrates bony lucency surrounding the cochlea producing a double ring or fourth ring sign, with cavities communicating with the internal auditory canal bilaterally. Axial T2 SPACE MRI shows T2 hyperintense foci adjacent to the cochlea, consistent with active cavitary otosclerosis.
Clinical insight:
Cavitary otosclerosis is an advanced form of otosclerosis characterized by large bony cavities within the otic capsule, which can communicate with the internal auditory canal. The double ring or fourth ring sign on CT reflects pericochlear lucency and is a key diagnostic feature. When an internal auditory canal diverticulum is identified, the otic capsule should be carefully scrutinized for changes suggestive of otosclerosis. These cavities can produce a third window phenomenon, contributing to mixed or sensorineural hearing loss. MRI T2 SPACE sequences complement CT by demonstrating active foci of fibrovascular spongiotic bone adjacent to the cochlea.
Case courtesy of Dr. Liddy Ellis MBChB, Cardiff and Vale UHB, and Dr. Rick Wiggins MD, University of Utah Health.