Aneurysm of azygous anterior cerebral artery. A case report.

This report describes a patient with a fusiform aneurysm of an azygous anterior cerebral artery (ACA) associated with a ruptured saccular aneurysm at its distal end. Gross, microscopic, and radiological documentation of this anomaly is presented. It is suggested that in cases where the question of an unpaired ACA arises, a projection paralleling the radiological baseline be employed during angiographic studies thus affording better visualization of these vessels. Clinically, in patients with pericallosal aneurysms, their frequent association with azygous ACA's should be borne in mind, as injury to this common arterial trunk will affect both hemispheres and the corpus callosum with tragic results.