部分血栓化した巨大本幹脳動脈瘤の臨床経過と病理所見 : 慢性解離性脳動脈瘤の概念 : 椎骨脳底動脈thrombosed aneurysmの病態と治療  [in Japanese] Clinicopathological Study of Partially-thrombosed Dolichoectatic Cerebral Aneurysms: A Proposed Concept of "Chronic Dissecting Aneurysm"  [in Japanese]

脳動脈全体が部分的に血栓化を伴って巨大化する本幹動脈瘤の存在は, 以前から知られていたが, 長期予後, 臨床経過はながらく不明であった. 診断時にはかなりの大きさに成長している場合が多く, giant fusiform aneurysm, megadolichoartery, giant serpentine aneurysmなどと呼称されてきた. これは, われわれの行った脳血管の本幹動脈瘤の分類でtype3に相当する. こうした部分血栓化巨大本幹動脈瘤の発生, 増大に関して, 今まで著者らが得た知見を報告する. 対象, 方法 1987年から2000年までの間に, 12例の部分血栓化した症候性の本幹動脈瘤を経験し, 最長10年のfollow upを行った. 正確な頻度は不明であるが, われわれの脳神経外科施設において, だいたい入院患者700-800人に1人の割合であった. 患者はすべて男性で, 初診時の年齢は42-71歳であった. 動脈瘤の存在部位は脳底動脈が10例で, 椎骨動脈が2例であった. 軽度の高血圧, 高脂血症を有するものが一部存在した.

Little is known about the generatic mechanism and long-term clinical course of dolichoectatic aneurysms. We experienced and followed 12 patients with symptomatic partially thrombosed dolichoectatic aneurysms involving the whole vertebral and/or basilar arteries. Based on the clinical data, radiological images and pathological findings, we studied the generatic mechanism of dolichoectatic aneurysms. Twelve aneurysms involved 10 basilar arteries and 2 vertebral arteries. The 10 basilar aneuryms chronically grew to a giant size and finally caused death. Eight patients died of subarachnoid hemorrhage and 2 died of brainstem compression. Seven patients were autopsied. The average time between first diagnosis and death was 3 years and 10 months. The wall of the aneurysm basically consisted of adventitia and thickened intima. Media and internal elastic lamina almost disappeared. Vascular smooth muscle cells, which reproduce extracellular matrix, were diminished, and the wall of the aneuryms consisted almost entirely of loose collagen fiber networks. Early-stage MRI showed intimal flaps and autopsy confirmed dissection of thickened intima. We present the concept of "chronic dissecting aneurysm" regarding the generatic machanism of symptomatic partially thrombosed dolichoectatic aneurysms.