Progressive multifocal leukoencephalopathy developing in a fludarabine naïve patient with chronic lymphocytic leukemia.

We report a case of progressive multifocal leukoencephalopathy developing in a fludarabine-naïve patient with chronic lymphocytic leukemia. We suggest that progressive multifocal leukoencephalopathy should be considered in any chronic lymphocytic leukemia patient with unexplained neurological symptoms. Treatment history does not necessarily require fludarabine. Intrathecal cytosine arabinoside although unsuccessful in this patient, is a therapeutic option to consider in patients experiencing side effects from systemic therapy.