Background: An aneurysm originating from the junction of the A1 segment of the anterior cerebral artery and accessory middle cerebral artery (Acc-MCA) is markedly rare. We report a rare case of an Acc-MCA aneurysm, and discuss the clinical course and management of this rare condition.
Case description: A 64-year-old man with a past history of cerebral infarction was revealed to have a left Acc-MCA and an aneurysm at its origin. The aneurysm was clipped via a transsylvian approach. Due to its location and projectile direction, the neck of the aneurysm was left partially unclipped.
Conclusion: Although an Acc-MCA aneurysm is very rare, it has a potential risk of rupture. Therefore, radical treatment is necessary for such aneurysms.
Keywords: Accessory; aneurysm; anomaly; anterior cerebral artery; middle cerebral artery.