RL-MPV Followed by BBC HCT Using Autologous Stem Cells and Maintenance Therapy With Nivolumab for Newly Diagnosed PCNSL

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 70years-old. Patients must sign an informed consent. Exclusion Criteria: Prior cranial irradiation Other active primary malignancy. Pre-existing immunodeficiency such as renal transplant recipient. Prior treatment with chemotherapy for CNS lymphoma.