Chronic lymphocytic leukemia with central nervous system involvement: report of two cases with a comprehensive literature review.

Central nervous system (CNS) involvement is a rare complication of chronic lymphocytic leukemia (CLL) with varied outcomes. We contribute two additional cases of CLL with CNS involvement. The clinical course and response to treatment are described. All 78 previously reported cases of CLL with CNS involvement are presented in this comprehensive review of the literature. CNS involvement of CLL is a rare complication that does not seem to correlate with any evident risk factors. Resolution of CNS symptoms can often be accomplished with intrathecal chemotherapy or irradiation. Early detection and treatment may result in better outcomes in this rare complication.