Ibrutinib With Rituximab and Lenalidomide for Patients With Recurrent/Refractory Primary or Secondary Central Nervous System Lymphoma (PCNSL/SCNSL)

Inclusion Criteria: * Participants must be able to understand and be willing to sign a written informed consent document. * Men and woman who are at least 18 years of age on the day of consenting to the study. * Histologically documented PCNSL or histologically documented systemic diffuse large B-cell lymphoma (DLBCL). * Patients must have relapsed/refractory PCNSL or relapsed/refractory SCNSL * All patients need to have received at least one prior CNS directed therapy. There is no restriction on the number of recurrences. * Patients with parenchymal lesions must have unequivocal evidence of disease progression on imaging (MRI of the brain or head CT) 21 days prior to study registration. For patients with leptomeningeal disease only, CSF cytology must document lymphoma cells and/or imaging findings consistent with CSF disease 21 days prior to study registration (at the discretion of the investigator). * Participants must have an ECOG performance status of 0, 1, or 2. * Participants must have adequate bone marrow and organ function shown by: * Absolute neutrophil count (ANC) ≥ 1.0 x 10\^9/L * Platelets ≥ 75 x 10\^9/L and no platelet transfusion within the past 21 days prior to study registration * Hemoglobin (Hgb) ≥ 8 g/dL and no red blood cell (RBC) transfusion within the past 21 days prior to study registration * International Normalized Ratio (INR) ≤ 1.5 and PTT (aPTT) ≤ 1.5 times the upper limit of normal * Alanine aminotransferase (ALT) and aspartate aminotran…