Sensorineural Hearing Loss Caused By Labyrinthine Erosion Due To A Cerebrospinal Fluid Diverticulum

Objective: To present a case of progressive sensorineural hearing loss (SNHL) caused by labyrinthine erosion secondary to expanding geniculate ganglion cerebrospinal fluid (CSF) diverticulum extending along the path of the facial nerve. Patient: Thirteen-year-old man with no past medical history or risk factors presented with unilateral progressive SNHL and no other otologic or neurologic symptoms. Interventions: Audiological data as well as imaging studies including a magnetic resonance imaging (MRI) of the brain and internal auditory canal and a temporal bone computed tomography (CT) are presented. Partial labyrinthectomy, CSF leak closure, and cochlear implantation were performed. A lumbar puncture was obtained 2 months postoperatively. Main Outcome Measure: Closure of the CSF leak. Results: Mastoidectomy revealed a wide area of CSF leak through the geniculate ganglion and fallopian canal with partial destruction of the superior and lateral semicircular canals by an expanding diverticulum. Conclusions: This is an unusual presentation of progressive SNHL due to partial labyrinthine erosion due to a meningocele of the geniculate ganglion along the fallopian canal. It is likely that the patient had a congenital open pathway through the labyrinthine segment of the facial nerve and CSF pulsations created the meningocele over a few years. This case argues for early closure of such CSF diverticula to prevent possible SNHL due to labyrinthine erosion.