Meningiomas account for approximately 18 to 19 per cent of all brain tumours. Although they can arise in numerous locations, meningiomas of the internal auditory canal (IAC) are rare. Most tumours that originate in the IAC are schwannomas of the Vilith cranial nerve (acoustic neuromas). We report a case of a meningioma which appears to originate from the IAC and extends into the vestibule. The clinical findings and the radiographical features of meningiomas of the IAC are similar to those of acoustic neuromas. Pre-operative differentiation between acoustic neuromas and meningiomas of the IAC may be difficult.

A 42-year-old man with normal hearing presented with a long history of vertigo and tinnitus. CT scan showed large osteomata of the internal auditory canal. Magnetic resonance imaging (MRI) was normal. The osteomata were removed surgically via the retrosigmoid approach and examined histologically. His symptoms were abolished. As MRI has become the gold standard in the search for small acoustic tumours it is likely that symptomatic bony lesions, rare though they are, will be missed if MRI is the sole imaging modality. A review of the literature is included.

A case of an unilateral sensorineural hearing loss of sudden onset, due to an osteoma in the internal auditory canal is presented. As far as the authors are aware an osteoma at this site associated with a hearing loss occuring within a few hours has not previously been reported.