Radiation-induced Cerebrovasculopathyの1例

Radiation-induced Cerebrovasculopathy: A case report and review of the literature

I．はじめに

　脳腫瘍に対する放射線治療は直達手術困難な腫瘍や残存腫瘍の後療法として，また化学療法との併用によりその有効性が確立されている．近年は周辺正常脳組織への影響が最小限に抑えられしかもその治療効果をあげるべくガンマナイフによる治療も盛んに行われ，深部脳腫瘍や脳動静脈奇形等に対してその有効な治療成績が報告されている．一方，放射線照射による合併症の報告も多く，その一つとして照射後脳血管の狭窄，あるいは閉塞性変化をきたし，脳虚血症状を呈するいわゆるradia—tion-induced cerebrovasculopathyの報告も散見される．今回われわれは星細胞腫に対する放射線照射後に脳主幹動脈の狭窄，閉塞性変化をきたした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．

We reported a case of a patient who suffered from a cerebrovasculopathy after irradiation therapy for astro-cytoma located at the left temporal lobe. An eleven year-old boy who presented himself with headche and vomiting as his chief complaints received partial re-moval of a tumor. Histological diagnosis of the tumor was astrocytoma (grade II). His preoperative cerebral angio-grams showed mass sign solely, without stenosis or occlusion of the cerebral vessel. Postoperatively, he was treated with irradiation therapy involving the whole brain with a total of 30 Gy, and gamma knife therapy. Six months after irradiation, he started suffering from frequent cerebral ischemic attacks, but there was no re-growth of the tumor visible on CT scans. Cerebral angiograms were made again, and revealed multifocal stenoses in the bilateral internal carotid arteries, middle cerebral arteries, and the anterior cerebral artery. His symptoms did not improve after conservative treatment with steroids, calcium antagonist, or low molecular weight dextran. Although he received a superficial tem-poral artery-middle cerebral artery (STA-MCA) anasto-moses bilaterally, multiple cerebral infarctions appeared.

Although irradiation therapy is acceptable in patients with brain tumor, a cerebrovasculopathy after irradiation should be considered as one of the most important com-plications, and the risk incurred by irradiation therapy should lead to more careful consideration and caution when treating intracranial brain tumors, especially in children. From our experience, the usefulness of bypass surgery for radiation-induced cerebrovasculopathy is still controversial.