Hemiballismus in patient with blastic phase of chronic myelogenous leukemia

The authors report the clinical course and neuropathological findings in the case of hemiballismus due to leukemic infiltration of the subthalamic nucleus. The symptoms were observed in a 19-year-old patient with blastic phase of chronic myelogenous leukemia, two weeks before death, when what is called the "critical point" developed (white cell count beyond 100 G/l and thrombocytopenia less than 50 G/l). The investigation are considered to confirm the role of the "critical point" in the development of central nervous system leukemic complications.