Dramatic psychiatric and behavioral symptoms following a subthalamic lesion

•Neuropsychiatric symptoms following a subthalamic lesion have been rarely reported.•Subthalamic nucleus is part of the limbic circuitry associated with emotion and behavior.•Severe neuropsychiatric symptoms can occur from subthalamic lesion, and can be troubling.•Neuropsychiatric symptoms require more attention in the patients with a subthalamic lesion. Neuropsychiatric symptoms have been well documented after subthalamic nucleus deep brain stimulation (STN-DBS), but those following a subthalamic lesion have been rarely reported. Herein, we present a 43-year-old woman with sudden-onset dramatic psychiatric and behavioral symptoms with hemiballism. Brain magnetic resonance imaging (MRI) with fluid attenuated inversion recovery (FLAIR) sequence during the acute phase demonstrated extensive hyperintensity in the left STN and adjacent regions. Contrast-enhanced MRI showed no abnormal areas of enhancement. Magnetic resonance venography (MRV) was normal. Routine blood and cerebrospinal fluid (CSF) tests were not remarkable. Autoimmune antibodies showed no significant results. A gradual recovery of both psychiatric and behavioral symptoms and hemiballism was observed with steroid and symptomatic treatment. Our case is unique in dramatic neuropsychiatric symptoms following a subthalamic lesion. We would like to point out that severe neuropsychiatric symptoms can occur in the patients with subthalamic lesions, and can be a troubling feature in their management.