Study of the Effect of GM-CSF on Macrophages in Ependymoma

Inclusion Criteria: * Age \> 12 months and \< 21 years at the time of study enrollment. * Patients must be one of the following: • Newly diagnosed with posterior fossa ependymoma with a subtotal resection at initial surgery. These patients will be eligible for stratum 1. * Be in first relapse of their posterior fossa ependymoma. These patients will be eligible for stratum 2. * Histologically confirmed diagnosis of intracranial ependymoma . * Pre or post-operative MR imaging of the brain demonstrates no evidence of non-contiguous spread beyond the primary site * Pre or post-operative MR imaging of the spine demonstrates no evidence of non-contiguous spread beyond the primary site * Pre-operative CSF cytology obtained from the lumbar CSF space demonstrated no evidence of non-contiguous spread beyond the primary site. • The requirement for lumbar CSF examination may be waived if deemed to be medically contraindicated. * Patients must meet one of the following performance scores. • ECOG performance status scores of 0, 1, or 2. * Karnofsky score of ≥ 50 for patients \> 16 years of age or Lansky score of ≥ 50 for patients ≤ 16 years of age * Organ Function Requirements: Adequate renal function defined as: * Creatinine clearance or radioisotope GFR ³ 70ml/min/1.73 m2 or * A serum creatinine based on age/gender as follows: Age Maximum Serum Creatinine (mg/dL) Male Female 1 month to \< 6 months 0.4 0.4 6 months to \< 1 year 0.5 0.5 1 to \< 2 years 0.6 0.6 2 to \< 6 years 0.8 0.8 6 to \< 10 years 1 1 10 to \< 13 years 1.2 1.2 13 to \< 16 years 1.5 1.4 ≥ 16 years 1.7 1.4 The threshold creatinine values in this Table were derived from the Schwartz formula for estimating GFR (Schwartz et al. J. Peds, 106:522, 1985) utilizing child length and stature data published by the CDC. * Adequate liver function defined as: * Total bilirubin =\< 1.5 x upper limit of normal (ULN) for age, and * SGOT (AST) or SGPT (ALT) \< 3 x upper limit of normal (ULN) for age. * Patients with Gilbert syndrome or hemolytic anemia are eligible if total bilirubin is \< 3 x upper limit of normal (ULN) for age. * Adequate Bone Marrow Function defined as: * Peripheral absolute neutrophil count (ANC) \>= 1,000/uL * Platelet count \>= 100,000/uL (transfusion independent). Exclusion Criteria: * Patients with a diagnosis of spinal cord ependymoma, myxopapillary ependymoma, subependymoma, ependymoblastoma, supratentorial ependymoma, or mixed glioma are NOT eligible. * Patients with evidence of metastatic disease by MRI or CSF cytology are NOT eligible