脳実質内より発生した天幕上上衣腫の1例

Supratentorial Ectopic Ependymoma : a case report

I．はじめに

　上衣腫は脳室壁の上衣細胞から発生し，脳室近傍の白質あるいは脳室内へ進展する場合が多く，また頭蓋内に認められる上衣腫の約2／3がテント下に発生すると言われている^2,6,10,11）．今回われわれは脳室系との連続性を認めず，テント上で左頭頂葉の脳実質内より発生したと考えられる上衣腫の1例を経験したので若干の文献的考察を加えて報告する．

Ependymomas usually arise from the ventricular surface and approximately two-thirds of them are infra-tentorial. We present an unusual case of supratentorial ependymoma located in the parietal parenchymaand exhibiting no continuity with the ventricular system. On March 30, 1998, a 63-year-old woman wasadmitted to our neurosurgical service because of a sudden consciousness loss attack two weeks before. Onadmission, neurological examination revealed no abnormal findings. Computerized tomography (CT) re-vealed a mass lesion of the parietal lobe which was enhanced homogeneously. Magnetic resonance imaging(MRI) also showed the mass of the parietal lobe which was iso-intense on T1-weighted images, iso andhigh intense on T2-weighted images and homogeneously enhanced by administration of Gd-DTPA. In theangiography, left carotid angiograms showed a tumor stain. On February 26, 1998, total removal of thetumor was performed using stereotactic craniotomy with neuronavigator and intraoperative echography.After surgery, focal radiation therapy (56Gy) was carried out. The pathological diagnosis was cellularependymoma with partial clear cell components. Several kinds of tumor may occur in the cerebral paren-chyma. We conclude, however, that ependymoma has to be included in the differential diagnosis when the tumor location is distant from the ventricles.