Infusion of 5-Azacytidine (5-AZA) Into the Fourth Ventricle in Patients With Recurrent Posterior Fossa Ependymoma

Inclusion Criteria: * Diagnosis: Patients with histologically verified ependymoma, with recurrence or progression anywhere in the brain and/or spine. Patients are also eligible if they have refractory disease, which will be defined as residual tumor which has not been completely cleared despite prior treatments. To be eligible, patients' disease must have originated in the posterior fossa of the brain * Patient must have either measurable or evaluable tumor as assessed by MRI of the brain and total spine * An implanted catheter in the fourth ventricle or posterior fossa tumor cavity attached to a ventricular access device or agreement to have one placed. * A minimum of 7 days between last dose of systemic chemotherapy and/or radiation therapy and first infusion of 5-AZA into fourth ventricle * Life expectancy of at least 12 weeks in the opinion of the principal investigator * Lansky score of 50 or greater if ≤16 years of age or Karnofsky score of 50 or greater if \> 16 years of age * Existing neurological deficits must have been stable for a minimum of 1 week prior to study enrollment * Patients must have recovered from the acute toxic effects of all prior anticancer chemotherapy * Adequate bone marrow function defined by peripheral absolute neutrophil count (ANC) ≥ 500/μL, platelet count ≥ 50,000/μL (transfusion independent), and hemoglobin ≥ 9.0 gm/dL (may receive RBC transfusions) * Patient or patient's legal representative, parent(s), or guardian able to provide written informed consent. Exclusion Criteria: * Enrolled in another treatment protocol * Has received another investigational or chemotherapy agent or radiation therapy within 7 days prior to 5-AZA infusion into the fourth ventricle * Evidence of untreated infection * Pregnant or lactating women