A meningioma of the lateral cerebellomedullary cistern without dural attachment.

A rare case of a meningioma in the lateral cerebellomedullary cistern without dural attachment is reported. The tumor was attached to the choroid plexus out of the lateral recess, not in the fourth ventricle. The radiologic findings and operative approach differed from those for fourth ventricle meningiomas or cerebellopontine angle meningiomas. Magnetic resonance imanging is the most helpful preoperative diagnostic study for determining the precise location, volume and extent of the lesion and the site of attachment. Care was taken not to injure the lower cranial nerves and the tumor was totally removed except for a tiny piece which invaded the proximal portion of the posterior inferior cerebellar artery.