Phase II Study to Evaluate the Combination of Rituximab and DepoCyte® in the C5R Chemotherapy Protocol in Patients Between the Ages of 18 and 60 Years With Primary Cerebral Non-Hodgkin Lymphoma and Systemic Diffuse Large B-cell Lymphoma With Neuromeningeal Invasion at Diagnosis

Inclusion Criteria: * Primary cerebral or oculocerebral NHL not previously treated with chemotherapy or radiotherapy and diffuse large B-cell lymphomas, with cerebral and / or neuromeningeal involvement at diagnosis. * Diagnosis proved by histological or cytological examination of cerebral specimens, CSF or vitreous humour. * Diffuse large cell CD20+ lymphoma. * Men or women between the ages of 18 and 60 years. * Presence of a measurable target to evaluate response. * Negative serological tests for HIV, hepatitis B (except in cases of vaccination), hepatitis C. * Life-expectancy ≥ 3 months * Patient having given written consent to participate in this study. Exclusion Criteria: * CD20- lymphoma. * History of indolent lymphoma, treated or untreated. * Contraindication for one of the products used in polychemotherapy. * Known hypersensitivity to mouse antibodies. * Absence of measurable target to evaluate response. * History of cancer in the 5 years prior to inclusion except for cutaneous basocellular carcinomas and non-invasive carcinomas of the neck of the uterus. * Cardiac contraindication to treatment with anthracyclines or to hyperhydration: SEVERE DISTURBANCE OF HEART RHYTHM VENTRICULAR EJECTION FRACTION BELOW 50% HISTORY OF RECENT MYOCARDIAL INFARCTION * Previously known severe renal insufficiency and/or creatinaemia \>150 µM/L (apart from invasion of the kidneys by the lymphoma). * Total bilirubin \>30 µmol/L, ASAT, ALAT \>2.5 times the upper normal value (apart from invasion of the liver by the lymphoma). * Insufficient medullary reserve: PNL \< 1 G/L and platelets \<100 G/L (apart from invasion of the medulla by the lymphoma). * History of organ transplantation or other causes of severe immunosuppression. * Pregnant woman. * Patient incapable of keeping to regular monitoring.