Progressive multifocal leukoencephalopathy: clinical and radiographic features.

Between April 1982 and March 1984 7 pathologically confirmed cases of progressive multifocal leukoencephalopathy (PML) were diagnosed at our institution. Only 1 case had been seen in the preceding twenty years. Four patients had acquired immunodeficiency syndrome (AIDS). The others had chronic lymphocytic leukemia, Hodgkin's lymphoma, and systemic lupus erythematosus. All patients presented with progressive neurological deficits. In most, the initial computed tomographic (CT) scan was disproportionately less abnormal than the clinical findings. In 5 patients the first CT scan revealed hypodensities of the cerebral white matter which lacked mass effect and did not enhance with contrast agent. The lesions were observed to enlarge progressively on CT scans but often lagged behind the rate of clinical evolution. Although 3 patients were treated with cytosine arabinoside, none improved. PML had similar clinical, radiographic, and pathological features in the AIDS and non-AIDs patients. Of 79 AIDS patients cared for at our institution between December 1979 and December 1983, 3.8% had PML. PML should be suspected in AIDS patients in the presence of the characteristic CT features, especially when CT-clinical dissociation occurs.