[A Case of Embolic Infarction Associated with Accessory Middle Cerebral Artery and Treated Using Mechanical Thrombectomy].

The accessory middle cerebral artery(AMCA)is an anatomical variant of the MCA. It originates from the anterior cerebral artery, reaches the sylvian fissure, and supplies the territory of the middle cerebral artery. We report a case of embolic infarction associated with the AMCA that was treated using mechanical thrombectomy. An 82-year-old man with chronic atrial fibrillation experienced a sudden onset of left hemiparesis and was brought to our hospital. Magnetic resonance imaging showed a right temporal lobe, parietal lobe, and basal ganglion infarction, and indicated right internal carotid artery(ICA)occlusion. Mechanical thrombectomy using a Penumbra system was performed with complete recanalization. Final angiography revealed the existence of the AMCA, and the thrombus was located at the right ICA C2 portion to the main MCA. There have been twelve reported cases of ischemic stroke associated with the AMCA, including the present case. We summarized the data from the reported cases of ischemic stroke with an AMCA and evaluated their clinical characteristics and the pitfalls of endovascular treatment. These cases suggest that the AMCA may play a role in collateral flow around the main MCA occlusion, but provides insufficient collateral blood supply. Owing to the anatomical characteristics of the AMCA, we should pay attention to possible complications of endovascular treatment.