Primary CNS lymphoma and secondary involvement of the central nervous system

Primary NHL of the CNS (PCNSL) is a rare form of extranodal non-Hodgkin’s lymphoma (NHL) whose incidence has been increasing for the last three decades. More than 90% of PCNSLs are aggressive NHL of the B-cell type. Diagnostic measures and therapeutic management differ from those of other extranodal NHL. The prognosis is poor despite initially excellent responses to steroids and radiotherapy (RT). Adding methotrexate (MTX) to RT has improved the prognosis of PCNSL patients, although most eventually relapse. Early dose-intensified chemotherapy and peripheral stem-cell transplantation have shown high efficacy in clinical trials in younger patients. In treating elderly patients with PCNSL, the high risk of neurotoxicity should be considered; systemic chemotherapy without RT is recommended in those patients. The monoclonal antibody rituximab has produced promising results in small cohorts, but its value remains unproven. Secondary CNS lymphoma is associated with a fatal prognosis in most patients, and effective treatment has not been defined; however, PCNSL treatment strategies may be considered in those patients.