Inclusion Criteria

DISEASE CHARACTERISTICS:

- Diagnosed with meningioma

- WHO grade I-III

- Recurrent or progressive disease after prior surgery and radiotherapy, or
radiosurgery

- Not amenable to further surgery

- No optic nerve sheet tumor and neurofibromatosis type II

- No known brain metastasis

PATIENT CHARACTERISTICS:

- WHO performance status 0-2

- ANC > 1,500/mm^3

- Platelet count > 100,000/mm^3

- Hemoglobin ≥ 9 mg/dL (transfusion allowed)

- Total bilirubin < 1.5 times upper limit of normal (ULN)

- SGOT and SGPT < 2.5 times ULN

- Creatinine < 1.5 times ULN

- Negative pregnancy test

- Fertile patients must use effective barrier method contraception during and for up to
3 months after completion of study therapy

- No second malignancy

- No known chronic liver disease (i.e., active hepatitis, cirrhosis)

- No known HIV infection

- No significant history of non-compliance to medical regimens or inability to grant
reliable informed consent

PRIOR CONCURRENT THERAPY:

- See Disease Characteristics

- No concurrent enzyme-inducing anti-epileptic drugs

- No concurrent therapeutic anticoagulation with warfarin (e.g., Coumadin®)

- Low-molecular weight heparin (e.g., Lovenox) or heparin allowed

- Mini-dose Coumadin® (e.g., 1 mg QD) allowed for prophylaxis of central venous
catheter thrombosis, at the discretion of the treating physician

- No concurrent acetaminophen (Efferalgan®, Tachipirina®) allowed during imatinib
mesylate administration

- No other concurrent anticancer agents, including chemotherapy or biological agents

- No other concurrent investigational drugs