A Rare Case of Hearing Impairment due to Cerebello-Pontine Angle Lesion: Trigeminal Schwannoma.

Schwannoma of the trigeminal nerve is a rare condition. Even rarer is hearing loss occurring as a result of this lesion. The aim of this study is to highlight this rare cause of hearing impairment. Here we report the clinical features and findings of the imaging and audiological investigations of a case of trigeminal schwannoma diagnosed at our institution. Our patient presented with headache, giddiness, tinnitus, left-sided facial weakness, left-sided hearing loss, right-sided hemiplegia, and unintelligible speech. Radiological studies revealed a large well-defined mass lesion in the left cerebellopontine angle with a significant mass effect on posterior fossa structures, suggestive of trigeminal nerve tumor. Audio-vestibular assessment was done with pure tone audiometry, impedance audiometry, otoacoustic emission, brainstem-evoked response audiometry, and electronystagmography, which pointed toward a retrocochlear pathology for hearing loss and imbalance.