Aneurysm presenting as parkinsonism.

A 25-year-old man presented with a 3-month history of gradually progressive right side hemiparkinsonism. On examination his Unified Parkinson Disease Rating Scale motor score was 12 on the right side. There were no other abnormal neurologic findings. Brain MRI and angiography showed a giant thrombus containing aneurysm of the left middle cerebral artery compressing the left basal ganglia (figures 1 and 2). Initially the patient refused neurosurgical intervention. At follow-up 6 years later his neurologic status remained unchanged (video E-1). The patient underwent surgery in December 2005 and his hemiparkinsonism was almost abolished (video E-2). Secondary parkinsonism resulting from unruptured giant aneurysms is rare. A patient with parkinsonism due to a giant middle cerebral aneurysm which was abolished after surgical excision of the aneurysm has been reported,1 but there is another case in the literature with asymmetric parkinsonism, due to internal carotid artery aneurysm, which did not improve after internal carotid artery ligation.2