A distal anterior cerebral artery aneurysm arising from the middle of three A2 branches treated by stent-assisted coiling: a case report.

Distal anterior cerebral artery aneurysms (DACA) associated with complex anatomical variations of the anterior cerebral artery (ACA) are exceptionally rare. We report a rare case of a 78-year-old woman with a rare ACA configuration characterized by three distinct A2 branches, in which a saccular aneurysm developed at the bifurcation of the middle branch. The patient was admitted with sudden onset of headache, dizziness, nausea, vomiting, and hypertension. Computed tomography (CT) revealed subarachnoid hemorrhage. Computed tomography angiography (CTA) and digital subtraction angiography (DSA) revealed three distinct A2 branches arising from the ACA complex, with an aneurysm originating from the middle branch. On the eighth day after hemorrhage, stent-assisted coil embolization was successfully performed. Considering the close anatomical relationship between the aneurysm neck and the right superior trunk, a stent was strategically deployed in the right superior trunk to preserve distal cerebral perfusion. The postoperative course was uneventful, and clinical follow-up demonstrated an excellent neurological outcome. This case highlights the critical role of precise preoperative imaging evaluation (CTA, DSA) and individualized treatment strategies in managing complex vascular variations and associated aneurysms.