[Progressive encephalopathy in 3 cases of chronic lymphoid leukemia].

Three patients suffering from a lymphoproliferative syndrome developed, late in the course of the disease, a neurological disorder with the signs and symptoms of a progressive multifocal leukoencephalopathy (PML). This diagnosis was confirmed in the first patient. In the second, neuropathological examination revealed spongy and fibrous scars which could be evidence of an earlier lymphomatous infiltration. The diagnosis of the third patient was uncertain since no autopsy was made in this case. The involvement of the CNS in the evolution of lymphoproliferative disorders becomes more and more frequent, probably due to the prolonged survival time of patients undergoing chemotherapy and the immunosuppressive effects of such treatment. Biopsy is the only method of distinguishing PML from a cerebral leukemic infiltration; this is obviously important in view of the different therapeutic approaches used for the two diseases.