Massive cerebral edema associated with meningioma.

Cerebral edema is a well-known complication of malignant astrocytoma and metastatic brain tumour. Though far less frequent, the association of cerebral edema with meningioma is also recognized; this is unpredictable and sometimes out of proportion to tumour size. We describe three cases where the mass effect was due to severe edema, rather than the tumour itself and was responsible for a catastrophic clinical presentation. The mechanisms responsible for the development of severe edema with meningioma which have been previously proposed are reviewed. They include tumour size, location, histologic subtype, cellularity, mitotic activity, vascularity and the presence of excretory-secretory activity. None of these consistently correlate with cerebral edema. Our cases suggest that spontaneous hemorrhage into the tumour may be the common factor responsible for severe cerebral edema. It is stressed that though a decidedly rare complication, cerebral edema secondary to meningioma should be entertained in the differential diagnosis of acute neurologic deterioration of these patients.