Flow Diversion of a Thrombosed Middle Cerebral Artery Bifurcation Aneurysm Presenting With Ischemic Stroke: A Case Report.

Middle cerebral artery (MCA) bifurcation aneurysms typically present incidentally on imaging or with subarachnoid hemorrhage and are often managed surgically due to their peripheral location and complex anatomy. Ischemic stroke due to spontaneous Intrasaccular thrombosis is extremely rare and poses a management dilemma due to the combined risk of further thromboembolism and aneurysm rupture. A 68-year-old woman with a history of smoking presented with symptoms of a left MCA syndrome with acute left MCA territory infarcts on magnetic resonance imaging (MRI). Computed tomography angiography demonstrated a left MCA bifurcation aneurysm with an atypical luminal contour, which suggested intrasaccular thrombus. Vessel wall MRI supported the diagnosis of intrasaccular thrombus and aneurysm instability. In view of the risks of both recurrent thromboembolism and rupture, endovascular flow diversion was performed across the aneurysm into the superior division with initiation of dual antiplatelet therapy. The procedure was well tolerated and yielded excellent angiographic results. The management of partially thrombosed MCA aneurysms presenting with ischemic stroke remains challenging and is not well defined. Although flow diversion addressed both the thromboembolic and rupture risks in this case, it carries a significant risk of iatrogenic clot destabilization. Broader data collection through multicenter registries may help clarify the natural history and optimal management of this rare presentation.