<prompt> True about meningiomas -More common in men50 are malignant95 cure rate following treatmentArise from arachnoid layer  <response>: Meningiomas are tumors that arise from the dura mater and are composed of neoplastic arachnoid cap cells.They are now the most common primary brain tumor, accounting for approximately 32 of the total . this information has been added in 18the of Harrison.They tend to be more common in women and in patients with Neurofibromatosis type-2.Meningiomas are classified by the WHO into three histological grades of increasing aggressiveness: grade I or benign; grade II or atypical and grade III or malignantanaplastic. This information has been added in 18the of Harrison.Total surgical resection of benign meningiomas is curative. Tumors that cannot be resected ; may benefit from treatment with external beam radiotherapy or stereotactic surgery. 