The study will include 28 patients with primary CNS DLBCL who are ineligible with autologous hematopoietic stem cell transplantation or whole brain radiation therapy as consolidation therapy.~Induction treatment will include Rituximab and high dose methotrexate protocol (containing at least methotrexate and one more chemotherapy agent).~Patients with MRI documented response CR or PR after induction chemotherapy will enter the study protocol of lenalidomide maintenance (at a dose of 15 mg per day, on days 1 to 21 of each 28-day cycle) for up to 12 cycles or until the patients withdrew consent, the disease progressed, or unacceptable toxic effects occurred.~Maintenance therapy has to be started 6 weeks after the last dose of induction chemotherapy. Response evaluation by brain MRI has to be checked every 3 months after starting maintenance therapy.
The study will include 28 patients with primary CNS DLBCL who are ineligible with autologous hematopoietic stem cell transplantation or whole brain radiation therapy as consolidation therapy.~Induction treatment will include Rituximab and high dose methotrexate protocol (containing at least methotrexate and one more chemotherapy agent).~Patients with MRI documented response CR or PR after induction chemotherapy will enter the study protocol of lenalidomide maintenance (at a dose of 15 mg per day, on days 1 to 21 of each 28-day cycle) for a maximum of 12 cycles, withdrew consent, the disease progressed, or unacceptable toxic effects occurred.