Methotrexate and Etoposide Infusions Into the Fourth Ventricle in Children with Recurrent Posterior Fossa Brain Tumors

Inclusion Criteria: * Age 1 - 80 years at time of recurrence or progression * Diagnosis: Patients with histologically verified medulloblastoma, ependymoma, or atypical teratoid/rhabdoid tumor or other malignant brain tumor with recurrence or progression involving anywhere in the brain and/or spine. 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 an Ommaya reservoir 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 chemotherapy into fourth ventricle * Life expectancy of at least 12 weeks in the opinion of the PI * 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 Red Blood Cell transfusions) * Patient or patient's legal representative, parent(s), or guardian able to provide written informed consent. Exclu…