Progressive multifocal leukoencephalopathy in a case of acute lymphocytic leukemia.

Progressive multifocal leukoencephalopathy (PML) is a rare neurologic condition which usually occurs in patients with leukemia, malignant lymphoma, carcinomatosis, acquired immunodeficiency syndrome (AIDS) or a variety of other chronic disease process or in those on immunosuppressive therapy(l). The diffuse parenchyma! infection is caused by a group B human polyoma virus serotype (JC virus)(2). In children, it is even more fatal than adults(3).