Occluded middle cerebral artery vascular stump mimicking aneurysm: case report and review of literature.

The stump of an occluded middle cerebral artery (MCA) is a rare but important aneurysm mimic. A 57-year-old male was admitted due to recurrent onset of transient ischemic attack. Computed tomography angiography (CTA) and digital subtraction angiography (DSA) showed a total obstruction in the right MCA with moyamoya phenomenon at distal trunks and a protruding lesion in the left MCA bifurcation. The patient was diagnosed with left MCA bifurcation aneurysm. Intraoperatively, the lesion was found to be an occluded right MCA stump. Encephalomyoarteriosynangiosis was performed, and the patient remained symptom-free at the 6-month follow-up. The possibility of a vascular stump should be considered when an aneurismal lesion is present at the MCA bifurcation with moyamoya phenomenon at distal trunks.