Cochlear incomplete partition type III associated with hypothalamic hamartoma
Presentation
Bilateral SNHL since the age of 3, managed with hearing aids. History of type 1 diabetes and delayed onset puberty. Worsening hearing loss.
Patient Data
Bilateral normal cochlear size. The internal auditory meati are enlarged, with complete absence of modioli and spiral laminae, but present interscalar septa, demonstrating a "corkscrew" appearance. Vestibules and semicircular canals are irregularly shaped with cystic bulges. Findings are in keeping with cochlear incomplete partition (IP-III).
Dysmorphic, nonenhancing aspect of hypothalamus that follows cortical signal in all sequences, typical of hamartoma.
Area of white-gray matter junction blurring at the posterior aspect of the left superior temporal gyrus, associated with minimal cortical thickening and hyperintense white matter on FLAIR, in keeping with a Blumcke type I focal cortical dysplasia.
Case Discussion
Cochlear IP-III is the rarest non-syndromic genetic X-linked types of hearing loss 1. So far it has been considered an isolated entity, responsible for profound bilateral sensorineural hearing loss (SNHL), with a degree of conductive component due to changes in bony otic capsule 1,2.
Its association with hypothalamic abnormalities has been recently been described in a small number of pediatric patients 2.
While patients with moderate hearing loss can benefit from hearing aids, severe cases can only be managed with cochlear implants. Because of the abnormal communication between CSF and perilymphatic spaces, the procedure is at high risk for gushing during stapes manipulation 1,3.