Inclusion Criteria:

1. Lymphomatous meningitis documented by positive CSF cytology in either newly
diagnosed, relapsed or refractory primary CNS or systemic NHL

2. Pathologically diagnosed CD20-positive NHL

3. Age ≥ 18 years

4. ECOG Performance Status 0 - 2 (See Appendix A)

5. Life expectancy of at least 1 month

6. Informed consent must be given according to national/local regulations before
enrollment (See Appendix B)

7. Patients may have had prior CNS irradiation, intrathecal methotrexate, cytarabine or
thiotepa for treatment of lymphomatous meningitis but these treatments must have
completed at least two weeks before the study enrollment and the patients must have
recovered from any reversible toxicity caused by prior treatments

8. Concurrent systemic chemotherapy is allowed with the exception of high-dose
methotrexate (>500 mg/m2/day), high-dose cytarabine (>2 g/m2/day), high-dose thiotepa
(>300 mg/m2/day) or investigational agents

9. No concurrent intrathecal chemotherapy other than rituximab

10. No severe impairment of bone marrow function (ANC >1.5x109/L, PLT >50x109/L), unless
due to proven lymphoma involvement

11. No major impairment of renal function (serum creatinine < 1,5 x upper normal) or
liver function (ASAT/ALAT < 2,5 upper normal, total bilirubin <2,5x upper normal),
unless due to proven lymphoma involvement

12. No evidence of active opportunistic infections

13. No HIV infection

14. No pregnant or lactating status

15. Appropriate contraceptive method in women of childbearing potential or men

16. Absence of any psychological, familial, sociological or geographical condition
potentially hampering compliance with the study protocol and follow-up schedule;
those conditions should be discussed with the patient before registration in the
trial

17. Absence of a obstructive hydrocephalus or compartimentalization of CSF flow.