いわゆる"特発性ウィリス動脈輪閉塞症"（脳血管"Moyamoya"病）の病理学的検討

A PATHOMORPHOLOGICAL ANALYSIS OF SOCALLED "SPONTANEOUS OCCLUSION OF THE CIRCLE OF WILLIS" (CEREBROVASCULAR "MOYAMOYA" DISEASE)

　脳血管写上，主として脳底部の異常血管網を認め，両側または一側の頭蓋内内頸動脈終末部の狭窄ないし閉塞を示す疾患は，わが国の脳神経外科医によつて発見されたものであり^{19,20,32,45,47,48）}，特発性ウイリス動脈輪閉塞症^{14〜18,21,22）}，脳血管モヤモヤ病^{13,35〜44）}，　Cerebral juxta—basal telangiectasia^31）など種々の名称で呼ばれているが，従来日本人に多いことが一つの特異な点とされ，国外の報告は少なかつた。しかし最近になつてこの病態の存在が海外においても徐々に認識されるに至り世界的に関心が高まつて来た^{2,3,23,33,34,35,46,49〜51）}。

　しかし，報告されている臨床例のすべてが本症というべきものかは問題であり，その前にこの病態が果して単一の疾患単位ということができるか否かという基本的命題も未解決のまま残されている。

A pathomorphological study was made on six autopsy cases which had abnormal cerebral vascular network and occlusion around the circle of Willis especially of the terminal portion of the internal carotid artery.

In the terminal portion of the internal carotid artery, marked luminal narrowing occurred by the intimal thickening. Intimal thickening consists of fibrous connective tissue with or without lipid deposition. In general, internal elastic lamina is preserved.

In the anterior and middle cerebral artery, stenosis or obstruction due to edematous fibrous thickening of intima were observed. Internal elastic membrane showed marked concentric undulation. The media of the affected arteries was frequently thinned where the severe intimal fibrous thickening was observed.

Numerous dilated blood vessels in the lepto-meninx and/or branches of perforating arteries dis-tributing in the basal ganglia may correspond to the abnormal vascular network demonstrated on the cerebral angiogram.

No definite evidence of the congenital origin of the lesion was obtained, whereas several recent changes were recognized at the site of occlusion.

Besides the fibrous thickening of the intima, mural thrombosis may play a part at least in the progression of the stenosis. The causal genesis is, however, still remained obscure.

Within the cases which are clinically diagnosed as this disease, various lesions of different etiology may be involved.