Oculomotor Nerve Palsy Associated with Duplication of Middle Cerebral Artery, Anterior Communicating Artery Aneurysm, and Parietal Meningioma.

A 61-year-old male presents with diplopia of acute onset and progressive course. He has a history of previous intracranial haemorrhage that was surgically evacuated 7 years ago and was also associated with diplopia. Examination revealed left complete oculomotor nerve paralysis with a fixed and dilated left pupil. Computed tomography (CT) revealed encephalomalacia, evidence of previous craniotomy, and an incidental left parietal convexity meningioma. CT angiography of the brain revealed a left tortuous duplicate middle cerebral artery with fenestration of its proximal part, an anterior communicating artery aneurysm, and a characteristic capillary blush of the meningioma. Possible mechanisms of oculomotor nerve involvement are discussed.