[Hemi-ballistic involuntary movement manifested as an parietal lobe syndrome]

A 28-year-old man had a asymptomatic meningioma in right parasagittal parietal lobe. At surgery, the parietal lobe remarkably swelled before completion of total removal of the tumor, although any suggestive factor causing brain swelling was not found intraoperatively. CT scan was examined immediately after surgery and only revealed a small hematoma in the tumor bed without any additional lesion in thalamus or basal ganglia. It was inexperienced post-operative complication that involuntary hemiballistic movement of left limbs appeared immediately after recovery from general anesthesia, although the post-operative complications of right parietal lobe syndromes, such as left hemi-anesthesia, hemi-agnosia, hemiparesis and hemi-ataxia were predictable. The hemiballistic movement persisted for 2 days postoperatively and the other complications completely recovered in the next 3 months. MRI, taken at post-operative 14th day, did not detect any abnormal lesion in well-known responsible areas for hemiballismus such as subthalamus, thalamus and basal ganglia. We suppose that the parietal lobe, especially Broadmann's area 7 may be one of the responsible areas for provoking hemiballistic involuntary movement.