We describe a case of leukemia/lymphoma of Burkitt's type with relapsing meningeal disease treated with a combination of the intraventricular chimeric anti-CD20 monoclonal antibody rituximab and systemic high-dose cytarabine.Our patient is a 40-year-old male patient presenting with diplopia, dermal involvement, diffuse vertebral infiltration, bilateral pleural effusions, multiple lymphoadenopathies, and bone marrow blastic infiltration with the diagnosis of leukemia/lymphoma of Burkitt's type. Cytmorphological analysis of the cerebrospinal fluid (CSF) showed blasts that expressed a CD34þ/CD20þ/CD10þ immunophenotype. Systemic and intrathecal chemotherapy was administered according to the Berlin-Frankfurt-Muenster protocol [1] resulting in clinical, morphologic, immunophenotypic, and radiologic complete remission after four chemotherapic blocks and cerebrospinal radiotherapy (24 Gy).Before the fifth block he experienced an isolated meningeal relapse characterized by massive infiltration of CD34þ/CD20þ/CD10þ positive blastic cells.An Ommaya reservoir was positioned and five intrathecal courses of 15 mg methotrexate, 50 mg Ara-C, 4 mg dexamethasone along with block A of the BFM protocol, which included high-dose methotrexate, were administered. After an initial clearance of the CSF (1.74% CD19þ/CD20þ/CD10þ nucleated cells), the morphologic and immunophenotypic CSF examination performed after the fifth intratecal administration showed a progression of the disease with 5% of nucleated cells (NC) expressing CD19þ/CD20þ/ CD10þ.Four courses of intraventricular 25 mg rituximab with 4 mg dexamethasone were administered on alternate days with achievement of a good partial response (0.31% of NC with positivity of CD19þ/ CD20þ/CD10þ), without any adverse event. Two cycles of cytarabine (3 g/m 2 bd for 2 days) were further administered with complete morphological and immunophenotypical meningeal remission. After 35 months of follow-up the patient is still in complete remission with persistent CSF negativity.The introduction of rituximab in the treatment of CD20-positive lymphoid malignancies has raised the interest about its potential therapeutic efficacy in lymphoid cerebral involvement [2]. Based on the importance of direct complement-dependent cytotoxicity and apoptosis in rituximab-induced killing of lymphoma cells, pharmacokinetic studies have failed to demonstrate consistent rituximab CSF levels after systemic administration of conventional doses [3,4].Intraventricular injections of rituximab via Ommaya reservoir administered at a dosage of 10, 25, and 40 mg, respectively, resulted in total clearing of lymphoma cells in the CSF with persistence of the intraparenchymal masses in refractory primary CNS lymphoma [5], suggesting the safety and feasibility of intraventricular rituximab at a dosage less than 40 mg.Resistant/relapsing cerebral disease during the course of Burkitt's type leukemia/lymphoma harbors a poor prognosis. Based on the resistance occurring during a CNS oriented therapy, i.e., radiotherapy, multiple intra...