Yttrium Y 90 Ibritumomab Tiuxetan and Rituximab in Primary Central Nervous System Non-Hodgkin Lymphoma

Inclusion Criteria: * Patients with histological diagnosis of recurrent or refractory primary central nervous system (CNS) lymphoma with at least 1 measurable gadolinium enhancing lesion on brain MRI scans * Karnofsky performance status (KPS) \>= 60 * Patients could not have had more than 3 prior therapy regimens for the treatment of PCNSL * Absolute neutrophil count (ANC) \>= 1.5 x 10\^9/L * Platelets \>= 100 x 10\^9/L * Hemoglobin (Hgb) \> 10 g/dL * Serum total bilirubin =\< 1.5 x upper limit of normal (ULN) * Alanine aminotransferase (ALT) =\< 3.0 x ULN * Aspartate aminotransferase (AST) =\< 3.0 x ULN * Serum creatinine =\< 1.5 x ULN * Minimum interval since completion of radiation treatment is 12 weeks * Minimum interval since last drug therapy: * 3 weeks since the completion of non-cytotoxic agents * 4 weeks since the completion of a non-nitrosourea-containing regimen * 6 weeks since the completion of a nitrosourea-containing regimen * Patients must have signed an approved informed consent and authorization permitting release of personal health information * Patients are not on corticosteroids or on stable doses (less than 6 mg daily of dexamethasone) for more than 1 week before baseline imaging * Patients with the potential for pregnancy or impregnating their partner must agree to follow acceptable birth control methods to avoid conception * Patients must have no concurrent malignancy except curatively treated basal or squamous cell carcinoma of the skin or carcinoma in situ of the cervix and breast, adequately treated stage I or II cancer from which the patient is in complete remission; patients with other prior malignancies must be disease-free for \>= three years Exclusion Criteria: * Pregnant or breast-feeding women * Patients unwilling or unable to comply with the protocol * Other concurrent severe and/or uncontrolled concomitant medical conditions (e.g. active infection, uncontrolled diabetes, symptomatic congestive heart failure, unstable angina, cardiac arrhythmia, or psychiatric illness, etc.) that could cause unacceptable safety risks or compromise compliance with the protocol * Known diagnosis of human immunodeficiency virus (HIV) infection; prior radioimmunotherapy, prior myeloablative therapy with autologous bone marrow transplantation or peripheral stem cell rescue, and prior external beam radiation therapy to more than 25% of active bone marrow * Patients who have received filgrastim (G-CSF) or sargramostim (GM-CSF) within 2 weeks before treatment or major surgery within the prior 4 weeks