Posttraumatic hemiballism with focal discrete hemorrhage in contralateral subthalamic nucleus.

Although head trauma has occasionally been described as a cause of hemiballism, relevant traumatic lesion involving subthalamic nucleus (STN) has rarely been reported. We report a 49-year-old man with focal and discrete traumatic STN hemorrhage, which presented as transient contralateral hemiballism. Although such discrete STN lesion is not infrequently found in patients with post-stroke hemiballism, it has not been reported in posttraumatic hemiballism.