Malignant meningioma: clinical and pathological features.

The records of 15 patients with a diagnosis of malignant meningioma were reviewed. In one of these patients, in whom invasion of the brain and pituitary gland was the only unusual feature, the tumor was reclassified as benign. Seven tumors, four hemangiopericytomas and two transitional and one syncytial meningioma, were considered to be only borderline-malignant despite necrosis and invasion of the brain, because of few mitoses and regular architecture. Of this group of patients, four men and three women, two are alive and well, three died after incomplete resections, and two succumbed to recurrent tumor that had become inoperable. The other seven patients, six men and one woman, had lesions classified as histologically frankly malignant, on the basis of marked anaplasia and numerous mitoses. These comprised three hemangiopericytomas and three syncytial and one fibrous meningioma. One of these patients is alive and well and the others are dead, three a a result of metastases. The initial clinical course of malignant meningiomas tends to be short but is otherwise indistinguishable from that of benign meningiomas. The chances of recurrence and eventual death are high, and extracranial metastases are not rare. The tumors are most often hemangiopericytomas, but not exclusively so, and men are particularly at risk.