Oxaliplatin in Treating Children With Recurrent or Refractory Medulloblastoma, Supratentorial Primitive Neuroectodermal Tumor, or Atypical Teratoid Rhabdoid Tumor

DISEASE CHARACTERISTICS: * Histologically confirmed medulloblastoma, supratentorial primitive neuroectodermal tumor (including pineoblastomas and ependymoblastomas), or atypical teratoid rhabdoid tumor * Recurrent or refractory disease * Measurable disease by radiography * Patients with positive cerebrospinal fluid cytology or linear leptomeningeal disease are eligible PATIENT CHARACTERISTICS: Age * 21 and under Performance status * Karnofsky 50-100% OR * Lansky 50-100% Life expectancy * Not specified Hematopoietic * Absolute neutrophil count at least 1,000/mm\^3 * Platelet count at least 100,000/mm\^3 (transfusion independent) * Hemoglobin at least 8.0 g/dL (RBC transfusions allowed) Hepatic * Bilirubin no greater than 1.5 times normal * ALT less than 2.5 times normal Renal * Creatinine no greater than 1.5 times normal OR * Creatinine clearance or radioisotope glomerular filtration rate at least 70 mL/min Cardiovascular * Shortening fraction at least 27% by echocardiogram OR * Ejection fraction at least 50% by MUGA Pulmonary * No dyspnea at rest * No exercise intolerance * Pulse oximetry greater than 94% Other * No uncontrolled infection * No active graft-versus-host disease * No uncontrolled seizure disorders * Seizure disorders well controlled with anticonvulsants allowed * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception PRIOR CONCURRENT THERAPY: Biologic therapy * At least 2 weeks since prior growth factors * At least 6 months since prior allogeneic stem cell transplantation * No concurrent colony-stimulating factors during the first course of study * No concurrent immunomodulating agents Chemotherapy * At least 3 weeks since prior myelosuppressive therapy (6 weeks for nitrosoureas) and recovered * No other concurrent anticancer chemotherapy Endocrine therapy * If concurrent corticosteroids necessary for intracranial pressure, must be on stable or decreasing dose for at least 1 week prior to study * No other concurrent corticosteroids Radiotherapy * At least 2 weeks since prior local palliative radiotherapy (small port) to symptomatic metastatic sites * At least 3 months since prior craniospinal radiotherapy * No concurrent palliative radiotherapy * Recovered from prior radiotherapy Surgery * Not specified Other * No other concurrent anticancer or experimental drugs