Middle cranial fossa arachnoid cysts causing sensorineural hearing loss.

Arachnoid cyst of the middle cranial fossa has never been reported to present with sensorineural hearing impairment. We report the case of a 15-year-old girl who complained of progressive hearing loss on the right side for 4 years. The pure tone audiometry revealed sensorineural hearing loss with an average of 63 dB, and the auditory brain stem response demonstrated absence of all waves on the right side. Magnetic resonance imaging showed giant arachnoid cysts occupying the bilateral middle cranial fossa and extending to the parietal and prepontine areas with the atrophic change of the right facial-acoustic nerve cord and a decrease in signal intensity of the right cochlea and vestibule. The cystoperitoneal shunting procedure was suggested, but the parents hesitated about the surgical treatment. The patient has not received any surgical intervention, and her hearing has been stable for 1 year during the follow-up period. This case represents the first report that sensorineural hearing loss is a possible presenting symptom when arachnoid cysts of the middle cranial fossa are massive.