Ruptured proximal azygous anterior cerebral artery aneurysm.

The azygous anterior cerebral artery (AACA) is a rare anatomical variant, which is frequently associated with saccular aneurysms. These aneurysms are often located in the distal segment of the AACA. Proximal AACA aneurysms are rare and pose considerable challenges, both in radiological characterization and in management. We discuss the management issues in a 63-year-old man who presented with subarachnoid hemorrhage from a saccular AACA aneurysm.