Radiologic-Clinical Correlation Hemiballismus

A 65-year-old recently retired surgeon in good health developed disinhibited behavior over the course of a few months , followed by onset of unintentional, forceful flinging movements of his right arm and leg. Magnetic resonance imaging demonstrated a 1-cm rimenhancing mass in the left subthalamic region , which was of high signal intensity on T2-weighted images (Figs 1A-E). Positive serum human immunodeficiency virus antigen and antibody titers were found , with mildly elevated cerebrospinal fluid toxoplasma titers . Anti-toxoplasmosis treatment with sulfadiazine and pyrimethamine was begun, with resolution of the hemiballistic movements within a few weeks and decrease in size of the lesion. A stereotactic biopsy was performed but was nondiagnostic.