[Cerebrovascular moyamoya disease associated with aneurysm at the peripheral portion of the posterior chorioidal artery (author's transl)].

Three adult cases of cerebrovascular Moyamoya disease associated with aneurysmal shadow at the peripheral portion of the posterior choriodial artery are reported. According to the follow-up study of carotid angiograms, this aneurysmal shadow is considered to be a pseudo-aneurysm, which indicates a bleeding point in the brain tissue. It has generally been thought that the mechanism of the occurrence of the symptom in adult patient with cerebrovascular Moyamoya disease is due to rupture of vessels in the subarachnoid space on the brain surface. But from our experience, it is suggested that there should be another mechanism, beginning with rupture of vessels in the brain tissue.