[Primary central nervous system lymphomas].

Primary central nervous system lymphoma (PCNSL) is a rare form of extranodal lymphoma (nearly always non-Hodgkin's) and accounts for approximately 3 to 4% of primary brain tumors. PCNSL typically affects patients older than 60 years. Clinical features are variable and reflect the location of central nervous system lesion. Magnetic resonance imaging and stereotactic biopsy are the most important tools for diagnostic assessment. Chemotherapy based on high-dose of methotrexate (HD-MTX) and whole brain radiotherapy are the cornerstones of treatment. Radiotherapy is usually omitted in individuals older than 60 years because of high risk of unacceptable delayed neurotoxicity. Treatment of PCNSL should be started as soon as possible after diagnosis because delay in treatment may shorten the patients' survival.