Persistent primitive olfactory artery aneurysm.

A hypertensive 69-year-old man presented with an incidentally discovered non-ruptured aneurysm of the persistent primitive olfactory artery (POA). The POA originates at the terminal portion of the internal carotid artery, runs along the olfactory tract anteriorly toward the crista galli, and forms an acute angle with the distal anterior cerebral artery. The aneurysm was located at this characteristic acute angle. The persistent POA aneurysm associated with an anterior communicating artery aneurysm with wide neck was successfully treated by clipping surgery.