Chronic lymphocytic leukemia and the central nervous system: a clinical and pathological study.

Chronic lymphocytic leukemia is the most common human leukemia but infrequently causes neurologic symptoms. We have reviewed all previously reported cases of chronic lymphocytic leukemia in the CNS along with three new cases; one patient was diagnosed antemortem and treated with immediate improvement and 4-year survival. In addition, we reviewed all autopsy cases since 1972 and available lumbar puncture data on patients with chronic lymphocytic leukemia admitted to the Massachusetts General Hospital. Invasion of the CNS by chronic lymphocytic leukemia often leads to confusional state, meningitis with cranial nerve abnormalities, optic neuropathy, or cerebellar dysfunction. Lumbar puncture shows a lymphocytosis consisting of monoclonal B cells, but CSF cytology studies are of limited value in establishing the diagnosis. Long-term survival may be related to the stage of chronic lymphocytic leukemia at the time of CNS disease and may be associated with intrathecal chemotherapy. A mild, asymptomatic infiltration of the brain, frequently noted in late-stage chronic lymphocytic leukemia in autopsy series, may explain the CSF lymphocytosis in some patients with late-stage chronic lymphocytic leukemia.