Biological features of meningiomas that determine the production of cerebral edema.

Although meningiomas are known to cause varying degrees of cerebral edema, the relative importance of their location, size, histological subtype, and other histological features in the production of cerebral edema has not been studied adequately. Therefore, we undertook a retrospective analysis of 43 meningiomas excised between 1975 and 1980. The results indicate that histological subtype has no relationship to the production of cerebral edema, with one exception. Meningiomas containing partly or completely a hemangiopericytic component were the only histological subtype associated consistently with cerebral edema. The location of a meningioma per se may not determine the production of cerebral edema. A relationship between size, aggressive histological features, vascular proliferative changes, and the production of cerebral edema was seen. The need for and the nature of further studies required to explain the cerebral edema that may be associated with small meningiomas are discussed.