Middle cerebral artery fenestration presenting with cerebral ischemia: a case report and review of the literature.

Background: Middle cerebral artery (MCA) fenestration is a rare vascular variant that can mimic stenosis. Its association with cerebral ischemia remains controversial. Method: We report the case of a 53-year-old man with a history of transient ischemic attack (TIA), initially misdiagnosed with left MCA occlusion, who presented with sleep disturbances due to fear of stroke recurrence. A definitive diagnosis of MCA fenestration was established by digital subtraction angiography (DSA) and high-resolution magnetic resonance vessel-wall imaging (HRMR-VWI). Perfusion-weighted imaging (PWI) was employed to evaluate the associated hemodynamic compromise. A literature review was conducted to identify all reported cases of MCA fenestration associated with cerebral ischemia. Results: A total of 19 cases (including ours) from 12 studies were identified. Patients were predominantly male, with ages ranging from 4 to 85 years. All fenestrations were located in the M1 segment. Slit-like morphology was observed in 73.7% of patients and was more frequent in acute ischemic stroke (AIS) than in TIA (91.7% vs. 42.9%). Eleven patients (57.9%) were definitively diagnosed via DSA. Mechanical thrombectomy was performed in six patients with concurrent MCA occlusion, yielding favorable functional outcomes in five (83.3%). Overall, 73.7% of patients achieved favorable outcomes at follow-up. Conclusion: MCA fenestration should be considered in the differential diagnosis for patients presenting with cerebral ischemia and M1 stenosis or occlusion, particularly in the absence of conventional vascular risk factors. A slit-like morphology may be associated with a higher risk of stroke. Multimodal imaging is essential to avoid misdiagnosis and guide appropriate clinical management.