Premeatal and Retromeatal Cerebellopontine Angle Meningioma. Two Distinct Clinical Entities

Abstract

The topological classification of CPA-meningiomas according to their location anterior or posterior to the ICA is important, because the clinical presentation, the surgical strategy to be applied, and the functional outcome of critical neural structures differ between the two subtypes. Our results provide substantial evidence for the paradoxical observation that premeatal meningiomas have a significantly worse postoperative functional outcome compared to retromeatal meningiomas although premeatal meningiomas become symptomatic earlier and at smaller sizes.

Classification of Meningiomas in the Cerebellopontine Angle

“…They only displace, but do not infi ltrate the facial-cochlear nerve complex. As described by us earlier (Schaller 2003a , b ;Schaller et al 1999a ), the Vth cranial nerve was frequently displaced to the superior surface of the tumour, and the lower cranial nerves (IX-XI) were often distorted towards the foramen magnum. For these reasons, auditory and facial nerve function were found to be preserved postoperatively.…”

“…Some CPA meningiomas may remain asymptomatic for a patient's lifetime or be detected incidentally when a patient has a neuroimaging for unrelated symptoms. Symptoms are typically present a mean of 2.5-5 years before the actual diagnosis (Schaller et al 1995(Schaller et al , 1999a. The presenting signs and symptoms depend on the size and location/extent of the tumor as described earlier here and can be related to brainstem compression, cerebellar compression, cranial nerve involvement as well as increased intracranial pressure caused by mass effect or hydrocephalus (Schaller et al 1995(Schaller et al , 1999a.…”

“…It may grow outward toward the skull, causing the skull to thicken (Samii and Ammirati 1991 ;Samii and Draf 1989 ;Schaller 2005 ). Some of them may also contain cysts, small deposits of calcium or tightly packed bunches of blood vessels (Schaller et al 1995(Schaller et al , 1999a.…”

“…Meningiomas compromise of approximately 12.5% of all intracranial neoplasms and occur at frequency of 5-8% in the cerebellopontine angle (CPA) (Langmann et al 1990 ;Schaller et al 1999a ;Schaller 2003a , b ;Spiriev et al 2012 ). Next to vestibular schwannomas (VS), meningiomas represent the second most common tumor in the CPA with a prevalence of 3-13% of all CPA lesions.…”

The Classification of Posterior Petrous Meningiomas and Its Clinical Significance

“…They found the clinical manifestations were different between these two types. 18 According to the dural attachment of the meningioma, Schaller et al 7 divided them into premeatal and retromeatal meningiomas, and showed that premeatal meningiomas have a significantly worse post-operative functional outcome than retromeatal meningiomas, although premeatal meningiomas became symptomatic earlier and had smaller sizes. Desgeorges et al 19 classified the posterior surface of the petrous bone into three equal zones according to imaging manifestation: 19 Voss et al 4 classified posterior petrous meningiomas into four types: retromeatal, premeatal, suprameatal and inframeatal.…”