乏突起膠腫に対する放射線治療後に生じた頭蓋内仮性脳動脈瘤の1例

Intracranial Pseudoaneurysm Arising after Radiotherapy for Oligodendroglioma:A Case Report

Ⅰ．はじめに

　神経膠腫患者の予後が延長し，治療後，長期間で発生する合併症を診療する機会が増加している．頭蓋内血管狭窄や脳動脈瘤，もやもや病といった血管性障害の発症も報告されており¹³⁾，治療後のフォローアップにおいて念頭に置くべきである．脳動脈瘤が発見された場合，無症候性であれば経過観察も選択肢となるが，破裂瘤の場合には治療介入が必要となることが多い．

　今回，われわれは，神経膠腫の初期治療後，フォローアップにおけるMRIにて脳動脈瘤を診断し，バイパス術を併用したトラッピング術を行い，良好な経過を得た頭蓋内仮性脳動脈瘤の1例を経験した．放射線治療後の頭蓋内脳動脈瘤について，文献的考察を加えて報告する．

　Intracranial pseudoaneurysms arising after radiotherapy for brain tumors are a relatively rare occurrence and associated with high-volume radiotherapy such as stereotactic radiosurgery. Herein, the authors report a rare case of intracranial pseudoaneurysm after conventional radiotherapy for oligodendroglioma.

　Case:A 46-year-old female incidentally presented with an intracranial hemorrhage from a middle temporal artery aneurysm. Four years earlier, she underwent surgical resection and conventional radiation therapy for oligodendroglioma. The aneurysm was successfully treated with middle cerebral artery（MCA）aneurysm trapping, in conjunction with a parietal branch superficial temporal artery-MCA bypass, to prevent re-rupture. Formation of intracranial pseudoaneurysm after conventional radiotherapy is extremely rare. However, the occurrence of cerebral aneurysm(s), as well as vascular stenosis during follow-up for brain tumors treated with radiotherapy, should be considered.