Petrous Meningiomas I: An Overview

Abstract

Meningiomas of the cerebello-pontine angle (CPA) and the ventral petrous area account for approximately 8--23{%} of intracranial meningiomas or approximately 10--15{%} of the tumors in the CPA.1--3 Nakamura et al.1 presented a selected series of 421 CPA meningiomas, which seems to represent the largest series presented so far from a single institution. Clinical symptoms leading to diagnosis lasted from 14 to 4 years5 and include the symptoms which are characteristic for lesions of the CPA: symptoms of the cranial nerves (CNs) V--VIII, in the order of the predominance (6), hearing loss (73{%}), cer-ebellar signs (32{%}), trigeminal neuropathy (16{%}), and facial nerve dysfunction (16{%}). In addition, depending on their size symptoms of compression of the pons such as gait disturbance and obstructive hydrocephalus in 10--20{%} of these patients were observed.7,8 Rarely trigeminal neuralgia, even on the contralateral side, due to mass effect9 or hemifacial spasm,10--12 dizziness and vertigo, symptoms of the lower cranial nerves, have been reported. As with other CPA tumors, meningiomas can also be asymptomatic for a long period of time or be discovered during cranial imaging for other reasons. Similar to vestibular schwannomas because of frequent involvement of the internal auditory meatus and early involvement of hearing, these tumors have been evaluated and managed both by neurosurgeons and otologic skull base surgeons. Both surgical disciplines should join efforts to optimize therapy for these tumors located in a challenging area, particularly also because symptoms may lead patients initially to otologists. In the following, however, a rather neurosurgical perspective is outlined to describe access to and treatment of these meningiomas, with a special reference given as to when otologic cooperation is particularly appreciated.