The vascular component in meningiomas associated with severe cerebral edema.

Cerebral edema is usually a complication of the later growth stages of intracranial neoplasms. Three patients with small meningiomas presented with unusually several cerebral edema out of proportion to the size of tumors. All three tumors exhibited benign meningothelial components, the formation of pseudopsammoma bodies, and striking vascular mural proliferation of small dark cells. In two tumors ultrastructural examination of these cells showed features of pericytes. The vascular pericytic component in these tumors may grow more actively than the meningothelial component and thus may cause the production of severe cerebral edema. The clinical, radiological, operative, and light and electron microscopic findings are presented, and the relationship to angioblastic meningiomas is discussed.