硬膜付着をもたないシルビウス裂内髄膜腫の1手術例

Deep Sylvian Meningioma without Dural Attachment: A Case Report

Ⅰ．はじめに

　髄膜腫はくも膜の表層細胞（arachnoid cap cell）から発生し，その多くは術中に硬膜との付着が確認される．しかしときに硬膜との付着をもたない場合も存在し，脳室内に発生する髄膜腫（meningioma）はその典型であるが，シルビウス裂内部に限局したいわゆる“deep sylvian meningioma”の頻度は極めて少ない．今回われわれは同部位の髄膜腫の手術例を経験した．腫瘍はシルビウス裂深部で中大脳動脈およびその穿通枝と強く癒着しており，同部位が発生母地と考えられた．実際の手術所見を提示し，本腫瘍の臨床的特徴についての文献的考察を行ったので報告する．

　A 34-year-old female presented with an 8-year history of temporal lobe epilepsy. Magnetic resonance imaging showed a multilobular,well-demarcated and homogeneous tumorous lesion of 5 cm in diameter deep in the left sylvian fissure. Intraoperative findings revealed that the tumor was mainly in the left insular region without dural attachment and strongly adhered to the left middle cerebral artery and its perforators. The histopathological diagnosis was transitional meningioma without malignancy. There are few reported cases of deep sylvian meningioma without dural attachment. We review the literature and summarize the clinicopathological characteristics of this condition.