1) Out of 160 primary meningeal tumors surgically treated, 10 cases had histologically malignant tumors. Of them two cases of sarcoma and one case of meningioma with marked invasiveness were filed in malignant (sarcoma) group, and six cases of angioblastic meningioma of hemangiopericytoma type and one case of meningioma with partial invasiveness in semi malignant group. 2) Average duration of s...