Treatment of Acute Lymphoblastic Leukemia or Aggressive Lymphoma With Relapse in Central Nervous System With Depocyt

Inclusion Criteria: * proven diagnosis of ALL or very aggressive Non-Hodgkin-Lymphoma (Burkitt/Burkitt-like) and CNS relapse * CNS involvement demonstrated by a positive ventricular or lumbar CSF cytology or characteristic signs and symptoms of neoplastic meningitis plus an MRI or CT scan indicating the presence of meningeal involvement * in combined relapse in CNS and other locations: systemic therapy with CNS active drugs can be postponed for at least 2 weeks * Karnofsky Performance Score is \> or = 60% * 18 years of age or older * free of uncontrolled infection * recovered from any grade III / IV toxicities attributable to prior treatment with the exception of hematotoxicity * patient not pregnant or breast feeding and effective methods to prevent pregnancy * free from severe heart, lung, liver or kidney dysfunction * written informed consent Exclusion Criteria: * failed to respond (as defined by no clearance of the CSF) to \> 1 dose of prior i.th. MTX or ARAC or triple therapy * history of neurotoxicity (grade III - IV) attributed to i.th. or systemic HD therapy with MTX or ARAC * prior CNS relapse \< 1 month before