Hemiballismus due to contralateral sphenoid ridge meningioma.

Primary intracranial tumour is a very uncommon cause of hemiballismus. In our review of the literature only two verified cases were found: one meningioma and one meningoblastoma. We report a patient with right hemiballismus due to a contralateral meningioma of the sphenoid ridge. His symptoms disappeared completely after resection of the tumour. The patient had no signs of increased intracranial pressure. Possible pathogenic mechanisms are briefly discussed. A consequence of such an experience is that magnetic resonance imaging or computed tomography scans should be made of every patient with uncommon extrapyramidal disorders, particularly if they do not respond to drug therapy.