Primary central nervous system lymphoma: a review

Primary central nervous system lymphoma (PCNSL) is an aggressive non-Hodgkin's lymphoma associated with a poor prognosis without treatment. The incidence in immunocompetent patients appears to be increasing. Patients present with nonspecific neurologic symptoms or visual symptoms and contrast-enhancing lesions that abut a cerebrospinal fluid (CSF) space. A subset of patients have positive CSF cytology or ocular involvement. Tissue diagnosis is accomplished by stereotactic biopsy, CSF cytology, or vitreous aspirate. Corticosteroids may obscure the results of tissue specimens and are best avoided prior to tissue diagnosis. PCNSL has emerged as a treatment- sensitive tumor responsive to corticosteroids, radiotherapy, and methotrexate-based chemotherapy. The most effective treatment program has not yet been identified, but it is clear that regimens containing high-dose methotrexate improve survival over radiotherapy alone. Because combined chemo-radiotherapy has been associated with late neurologic toxicities, especially in patients over the age of 60 years, chemotherapy without radiotherapy is being explored further. Significant progress in the treatment of PCNSL has been made in the past 10 years. Further progress will depend heavily on improved understanding of lymphoma biology, and future trials need to focus on improving survival rates while avoiding late neurologic toxicity.