PICA Communicating Arteryに発生した多発性動脈瘤の1例

Multiple Aneurysms of the PICA Communicating Artery : a case report

I．はじめに

　後下小脳動脈（PICA）の形態はバリエーションに富み，全体の32％で一側のPICAの低形成が，また4％では欠損が見られる^1）．このような場合，一側のPICAからvermisを越えてarterial bridgeを形成し，communicating vesselとして対側へ還流していることが珍しくない．Hlavinら^5）は，そのarterial bridgeに発生した動脈瘤を“aneurysmof the PICA communicating artery”と呼び，初めて報告している．今回われわれが経験した1例は同血管に発生した動脈瘤としては3例目であるが，多発例としては初めての報告であり，興味深いと思われたので報告する．

A case with unusual type of aneurysms in the distal posterior inferior cerebellar artery (PICA) is re-ported here. Though only two cases with a single aneurysm of the PICA communicating artery have beenreported previously, the present case is the first one with multiple aneurysms in the PICA communicatingartery. A 61-year-old woman with a sudden onset of severe headache, vomiting and unconsciousness wastransferred to our hospital. CT scan revealed a hematoma in the fourth, third, and lateral ventricles, and amild subarachnoid hemorrhage at the posterior fossa. Cerebral angiogram showed the right PICA sup-plying the hypoplastic left PICA territory through an anastomotic vessel. Two small aneurysms were seenat the tips of hairpin curves of an anastomotic vessel, “the PICA communicating artery”. Suboccipital cra-niotomy was performed, and the ruptured aneurysm was clipped and the unruptured one was wrappedwith cotton-sheet. After the operation, her clinical recovery went well and she was discharged on foot.