Sufficient collateral blood supply from accessory middle cerebral artery in a patient with acute ischemic stroke.

We reported a case of acute embolic occlusion of the middle cerebral artery with a patent accessory middle cerebral artery. Because of the presence of sufficient collateral blood supply from the accessory middle cerebral artery, the patient only underwent transient ischemic attack and did not need endovascular treatment. There was mild infarction in the basal ganglia and temporal lobe, NIHSS score of the patient at discharge seven days after stroke onset was 0, and modified Rankin scale score at 90 days was 0.