The purpose of this study is to determine whether combined chemotherapy [rituximab plus high dosage methotrexate (max. 2 cycles) followed by arabinoside/thiotepa (max. 2 cycles) followed by high dosage carmustin/thiotepa] followed by peripheral blood stem cell transplantation is effective in the treatment of cerebral Non Hodgkin lymphoma [PCNSL].

Inclusion Criteria:

• group A: first diagnosis of PCNSL, histologically confirmed
• group B: relapse or progression of PCNSL after MTX containing chemotherapy
• age 18 - 65 years
• not legally incompetent, physically or mentally incapable of giving consent
• written signed and dated informed consent of the legal representative and - if possible - of the patient

Exclusion Criteria:

• manifestations of further lymphoma outside the CNS
• sero-positive for HIV
• severe pulmonary, cardiac, hepatic, renal impairment
• neutrophil count < 2.000/µl, platelet count < 100.000/µl
• pulmonary disease with IVC < 55%, DLCO < 40%
• cardiac ejection fraction < 50%, uncontrolled malign arrhythmia
• creatinine > 1,5 mg% or creatinine-clearance < 50ml/min
• bilirubin > 2mg/dl
• ascites or pleural effusion (> 500ml)
• pregnancy o r lactation
• women with childbearing potential without sufficient contraception
• participation in another clinical trial within the last 30 days prior to the begin or parallel to this study
• known or current drug or alcohol abuse
• known hypersensitivity against methotrexate, cytarabine, thiotepa, BCNU rituximab, leukovorin, dexamethasone, neupogen and neulasta.