Bilateral posterior semicircular canal dehiscence in the setting of Hallermann-Streiff syndrome.

Hallermann-Streiff syndrome, also known as oculomandibulofacial syndrome, is a rare congenital disorder affecting growth and cranial, dental, ocular, pilocutaneous, and mental development. In addition to routine audiologic testing in patients with this syndrome, high-resolution computed tomography of the temporal bones should be performed in those with documented or suspected sensorineural hearing loss. Cochlear implantation may be considered, as in other children with syndromic hearing loss and certain inner ear abnormalities, if the appropriate audiologic, psychosocial, and medical criteria are met. The current case report radiographically and clinically characterizes inner ear dysplasia in an 8-year-old patient with Hallermann-Streiff syndrome. High-resolution computed tomography of the temporal bones revealed a hypoplastic bony island between the vestibule and horizontal semicircular canals, as well as incomplete bony coverage of the posterior semicircular canal crura bilaterally. To our knowledge, this is the first report of a pediatric patient demonstrating bilateral posterior semicircular canal dehiscence.