2005 年 45 巻 10 号 p. 523-525
A 67-year-old man presented with multiple aneurysms arising from the caudal loop of the posterior inferior cerebellar artery (PICA), possibly as a result of blunt trauma. Computed tomography of the head revealed subarachnoid hemorrhage in the posterior fossa and sylvian fissure. Repeated angiography demonstrated an aneurysmal dilatation and an irregular wall on the caudal loop of the PICA. Under the operating microscope, two lesions were observed 10 mm distal to the apex of the caudal loop, both consisting of a tiny hole on the vessel wall with a fragile fringe of connective tissue and covered with a firm clot. The height of the lesions corresponded to the C-l lamina, so the lesions were probably traumatic rather than saccular.