Imatinib Mesylate in Treating Patients With Recurrent Malignant Glioma or Meningioma

DISEASE CHARACTERISTICS: * Histologically confirmed recurrent or unresectable malignant glioma * Glioblastoma multiforme (phase I only) * Anaplastic astrocytoma * Anaplastic oligodendroglioma * Anaplastic mixed oligoastrocytoma * Malignant astrocytoma not otherwise specified * Gliosarcoma * Low-grade histology with subsequent diagnosis of malignant glioma allowed (phase I only) OR * Histologically confirmed recurrent or unresectable benign or malignant meningioma (phase I only) * No prior intracranial hemorrhage * Failed prior radiotherapy * Progressive or recurrent disease by MRI or CT scan and/or resection * PET or thallium scan, MR spectroscopy, or surgical documentation required in patients who have received prior interstitial brachytherapy or stereotactic radiosurgery * Stable dose of steroids for 5-7 days prior to MRI or CT scan PATIENT CHARACTERISTICS: Age: * 18 and over Performance status: * Karnofsky 60-100% Life expectancy: * More than 8 weeks Hematopoietic: * Absolute neutrophil count at least 1,500/mm\^3 * Platelet count at least 100,000/mm\^3 * Hemoglobin at least 10 g/dL (transfusion allowed) Hepatic: * Bilirubin less than 2 times upper limit of normal (ULN) * SGOT less than 2 times ULN * No significant hepatic disease Renal: * Creatinine less than 1.5 mg/dL * Creatinine clearance at least 60 mL/min * No significant renal disease Cardiovascular: * No significant cardiac disease * No deep venous or arterial thrombosis within th…