DISEASE CHARACTERISTICS:

• Histologically confirmed meningioma
• Recurrent or progressive disease after prior surgical resection
• Measurable disease by contrast-enhanced MRI
• Multifocal disease allowed

• No evidence of intratumor hemorrhage on pretreatment diagnostic imaging

  • Stable postoperative grade 1 hemorrhage allowed
• No peripheral edema or central or systemic fluid collections ≥ grade 2 (e.g., pericardial effusion, pulmonary effusion, ascites)

PATIENT CHARACTERISTICS:

• Karnofsky performance status 70-100%
• Absolute neutrophil count > 1,500/mm³
• Hemoglobin > 9 g/dL
• Platelet count > 100,000/mm³
• Potassium normal*
• Calcium normal*
• Magnesium normal*
• Phosphorus normal*
• AST and ALT < 2.5 times upper limit of normal (ULN)
• Bilirubin < 1.5 times ULN
• Creatinine < 1.5 times ULN OR creatinine clearance > 50 mL/min
• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception
• No excessive risk of bleeding, as defined by stroke within the past 6 months
• No active systemic bleeding (i.e., gastrointestinal bleeding or gross hematuria)
• No history of CNS or intraocular bleeding or septic endocarditis

• No concurrent severe and/or uncontrolled medical disease, including any of the following:

  • Uncontrolled diabetes
  • Congestive cardiac failure
  • Myocardial infarction within the past 6 months
  • Poorly controlled hypertension
  • History of labile hypertension
  • History of poor compliance with antihypertensive regimen
  • Chronic renal disease
  • Active uncontrolled infection requiring intravenous antibiotics
• No acute or chronic liver disease (i.e., hepatitis, cirrhosis)
• No HIV positivity

• No impairment of gastrointestinal function or disease that may significantly alter the absorption of imatinib mesylate, including any of the following:

  • Ulcerative disease
  • Uncontrolled nausea
  • Vomiting
  • Diarrhea
  • Malabsorption syndrome
  • Bowel obstruction
  • Inability to swallow tablets
• No other malignancy within the past 5 years except basal cell skin cancer or cervical carcinoma in situ NOTE: *Unless correctable with supplements

PRIOR CONCURRENT THERAPY:

• See Disease Characteristics
• Recovered from prior therapy
• More than 1 week since prior tumor biopsy
• More than 2 weeks since prior surgical resection
• Prior hydroxyurea allowed provided patient has not had progressive disease or toxicity > grade 3
• No prior imatinib mesylate or other platelet-derived growth factor-directed therapy

• At least 4 weeks since prior chemotherapy (6 weeks for nitrosoureas)*

  • Chemotherapeutic agents such as etoposide that are normally given at shorter intervals allowed even if < 4 weeks from last prior dose of chemotherapy
• At least 4 weeks since prior radiotherapy*
• At least 1 week since prior biological, immunotherapeutic, or cytostatic drugs
• At least 2 weeks since prior investigational drugs
• No concurrent warfarin NOTE: *Unless there is unequivocal evidence of tumor progression