[A case of multiple anomalies of cerebral vessels--fenestration of the middle cerebral artery aneurysm of the anterior communicating artery and arteriovenous malformation on the frontopolar region (author's transl)].

A case associated with multiple cerebral vascular anomalies, which consisted of fenestration of the middle cerebral artery, arteriovenous malformation and aneurysm of the anterior communicating artery, was reported. A 48 year-old male has been suffering from the left paralysis and mental disorder after the initial attack of subarachnoid hemorrhage, and the second attack resulted in the deterioration of the symptoms. He was admitted to our clinic on October 28, 1974. On neurological examination, mental disorders, such as disorientation, emotional incontinence, amnesia and acalculia, hemiplegia on the left and meningeal irritation signs were observed in admission period. Physical examination was negative. Cerebral angiographic findings were as follows: 1) Moderate vasospasm of the right internal carotid artery at the terminal segment, mild bowing of the anterior cerebral artery and stretching of the frontparietal opercular branches of the middle cerebral artery were observed. 2) Right frontpolar arteriovenous malformation fed by the frontobasal artery and the frontopolar artery, and drained via the aberrant cortical vein into the superior sagittal sinus. 3) Aneurysm of the anterior communicating artery was opacified by left carotid angiography. 4) An abnormal vessel derived from the terminal segment of the right internal carotid artery and terminated at the portion of the sphenoidal segment of the middle cerebral artery. Complete loop was formed between genuine middle cerebral artery and this abnormal artery. He was operated with dissecting microscope on November 11, 1974. The arteriovenous malformation at right frontopolar region was totally removed and aneurysm of the anterior communicating artery was clipped. According to the operative findings, the arachnoid membrane over the right frontopolar region was turbid and adhered to the adjacent tissues. On the contrary, no abnormal findings suggestive of previous subarachnoid hemorrhage were observed around the region of the anterior communicating artery aneurysm. These findings showed that subarachnoidal bleeding was caused by rupture of the arteriovenous malformation of right frontopolar region, but not by the aneurysm on the anterior communicating artery. The postoperative course was uneventful and during the hospitalization the patient starts on rehabilitation therapy. The authors discussed the genesis of fenestration of the middle cerebral artery and relation among these combined vascular anomalies. We inferred that fenestration of the middle cerebral artery arose from the in complete fusion of procursor vascular network in embryonic stage. Additionally, we emphasized that it was necessary to make a distinction between these two terms "fenestration" and "duplication".