BACKGROUND Endovascular therapy has been increasingly recommended for the treatment of acute ischemic stroke with large vessel occlusion of the anterior circulation. However, occlusions of the distal cerebral artery are not uncommon and may cause clinical deficits, especially when combined with ipsilateral chronic large vessel occlusion. Therefore in this patient population, the recognition of chronic occlusion and recanalization of the distal occlusive artery might be of great value for flow compensation. METHODS A 59-year-old male with a history of stroke was transferred to the emergency department with a severe right hemiplegia and aphasia syndrome. Head computed tomography demonstrated an old infarction focus of the left basal ganglia, and digital subtraction angiography revealed an occlusion of the left middle cerebral artery (MCA). After careful attempts, the microguidewire could not pass through the left MCA. On consideration of the patient's previous stroke history and the angiographic neovascularization, the left MCA was recognized as a chronic occlusion and its territory was supposed to be partly compensated by the ipsilateral anterior cerebral artery (ACA). A super-selective angiography of the left ACA demonstrated an occlusion of the callosomarginal artery. After a mechanical thrombectomy with a stent retriever, an angiogram showed complete recanalization and good antegrade reperfusion of the ACA supplying the partial MCA territory. The patient had a positive prognosis. CONCLUSIONS The recognition of chronic occlusion is crucial during acute mechanical thrombectomy, and distal thrombectomy may be beneficial after a careful full-scale assessment.