Methotrexate Infusion Into Fourth Ventricle in Children With Recurrent Malignant Fourth Ventricular Brain Tumors

Inclusion Criteria:

1. Diagnosis: Patients with histologically verified medulloblastoma, primitive neuroectodermal tumor (PNET), atypical teratoid/rhabdoid tumor (AT/RT), ependymoma, or choroid plexus carcinoma with recurrence or progression involving the brain and /or spine. Patients with these tumors who did not present at diagnosis in the posterior fossa but have relapsed in the posterior fossa will be eligible. Patients who initially presented with disease in the posterior fossa but have now relapsed outside the posterior fossa will also be eligible.
2. Patient must have either measurable or evaluable tumor as assessed by MRI of the brain and total spine.
3. An implanted catheter in the fourth ventricle attached to an Ommaya reservoir or agreement to have one placed.
4. A minimum of 7 days between last dose of systemic chemotherapy and/or radiation therapy and first infusion of methotrexate into fourth ventricle.
5. Life expectancy of at least 12 weeks in the opinion of the PI.
6. Lansky score of 50 or greater if ≤16 years of age or Karnofsky score of 50 or greater if \> 16 years of age.
7. Existing neurological deficits such as weakness, gait instability, cranial nerve deficits, or any other problems caused by the patient's disease or previous treatments must have been stable for a minimum of 1 week prior to study enrollment.
8. Patients must have recovered from the acute toxic effects of all prior anticancer chemotherapy.
9. 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)
10. Patient or patient's legal representative, parent (s), or guardian able to provide written informed consent.

Exclusion Criteria:

1. Enrolled in another treatment protocol
2. Has received another investigational or chemotherapy agent or radiation therapy with in 7 days prior to methotrexate infusion into the fourth ventricle
3. Evidence of untreated infection
4. Pregnant or lactating women