[Two cases of azygos anterior cerebral artery aneurysm (author's transl)].

Two cases with azygos anterior cerebral artery were reported from an analysis of 37 cases of distal anterior cerebral artery aneurysm. Case 1 was a 57-year-old woman. She had an attack of subarachnoid hemorrhage two months before admission to our clinic. The anterior cerebral artery was not demonstrated on the right carotid angiogram, and an azygos anterior cerebral artery was visualized on the left carotid angiogram. The aneurysm was situated at the distal end of the azygos artery. Case 2 was a 71-year-old hypertensive woman. Subarachnoid hemorrhage occurred 6 days before admission to our clinic. The left carotid angiography with contraleteral compression revealed an azygos artery and an aneurysm in its middle part. The azygos arteries in both cases were confirmed at operation and aneurysmal necks were managed without any serious deficit. The distal anterior cerebral artery aneurysm is frequently accompanied by azygos artery. This vascular anomaly may cause a hemodynamic change and may be one of the factors of aneurysmal formation at this part.