The International Tinnitus Journal

Neurootological Findings in Meningiomas of the Internal Auditory Canal and Cerebellopontine Angle

Meningiomas arise from arachnoid villi, the apparatus responsible for cerebrospinal fluid absorption, in proximity to a major vein or dural sinus and might also be present along neural foramina at the base of the skull. In the cerebellopontine angle (CPA), 80-90% of tumors are acoustic neurinomas and only 10-15% are meningiomas, which usually originate from the meningeal lining of the petrous bone adjacent to the sigmoid or superior or inferior petrosal sinuses. Meningiomas of the petrous bone can prolapse into the CPA and internal auditory canal (lAC) or can arise directly in the lAC, growing out into the CPA. As meningiomas usually do not invade the cranial nerves in the lAC and CPA, their surgical removal can be achieved with preservation of the facial, cochlear, and even vestibular nerves, provided that the operative approach does not destroy the labyrinth, as would occur in a transotic or translabyrinthine approach.