Abstract
A 54-year-old man presented with a rare ruptured distal middle cerebral artery (MCA) aneurysm manifesting as subarachnoid hemorrhage. Cerebral angiography demonstrated a fusiform aneurysm in the central artery of the left MCA. The patient underwent anastomosis between the superficial temporal artery and the central artery distal to the lesion followed by trapping and excision of the lesion. The postoperative course was uneventful. Histological examination of the excised specimen revealed a saccular aneurysm and absence of bacteria, inflammation, or neoplasm. The present case shows that a spontaneous saccular aneurysm can develop at the cortical segment of the MCA, and can be successfully treated with bypass surgery combined with trapping.