The 181 meningiomas studied included 173 classic (41 meningotheliomatous, 27 fibroblastic, 82 transitional, nine psammomatous, eight angiomatous and six hemangioblastic tumors) and eight malignant meningiomas (three hemangiopericytomas and five tumors that we labeled HFM, that is, tumors exhibiting evidence of histological features of malignancy).