Rituximab, Methotrexate, Procarbazine and Vincristine Followed by High-dose Chemotherapy With Autologous Stem-cell Rescue in Newly-diagnosed Primary CNS Lymphoma

Inclusion Criteria: * All patients must have non-Hodgkin's lymphoma involving the brain, as demonstrated by CT or MRI and histologic confirmation by one of the following: A positive CSF cytology for lymphoma or a monoclonal lymphocyte population as defined by cell surface markers. A biopsy of the vitreous or uvea demonstrating non-Hodgkin's lymphoma. Brain biopsy. * Patients must be HIV-1 negative. * Patient must have left ventricular ejection fraction ≥ 50%. * Patients must have no evidence of systemic lymphoma. This must be demonstrated by a CT scan of the chest, abdomen and pelvis prior to registration. * Patients must have adequate bone marrow function (defined as peripheral leucocyte count \>3000 cells/mm3 and platelet count \> 100,000 cells/mm3), liver function (bilirubin \< 2.0 mg%), and adequate renal function (serum creatinine \< 1.5 mg/dl or creatinine clearance \> 50cc/min/1.73M2). * Men and women of reproductive potential must agree to use an acceptable method of birth control during treatment and for six months after completion of treatment. * Patients must be between 18 and 72 years-old. * Patients must sign an informed consent. Exclusion Criteria: * Prior cranial irradiation * Other active primary malignancy with the exception of basal cell carcinoma of the skin and cervical carcinoma in situ. * Pre-existing immunodeficiency such as renal transplant recipient. * Prior treatment with chemotherapy for CNS lymphoma.