Imatinib Mesylate in Treating Patients With HIV-Related Kaposi's Sarcoma

DISEASE CHARACTERISTICS: * Histologically confirmed Kaposi's sarcoma (KS) involving at least 1 of the following areas: * Skin * Lymph nodes * Oral cavity * Gastrointestinal tract\* * Lungs\* NOTE: \*Must be asymptomatic or minimally symptomatic AND does not require systemic cytotoxic therapy * Serological documentation of HIV infection, as evidenced by positive enzyme-linked immunosorbent assay (ELISA), Western Blot test, or other federally approved licensed HIV test * At least 5 measurable, non-irradiated, cutaneous indicator lesions * Patients must have 3 lesions at least 5 x 5 mm that are accessible for 4 mm punch biopsy PATIENT CHARACTERISTICS: Age * 18 and over Performance status * Karnofsky 60-100% Life expectancy * At least 3 months Hematopoietic * Hemoglobin ≥ 8.0 g/dL * Absolute neutrophil count ≥ 1,000/mm\^3 * Platelet count ≥ 75,000/mm\^3 Hepatic * AST and ALT ≤ 2.5 times upper limit of normal * Bilirubin normal * Patients with elevated bilirubin secondary to indinavir or atazanavir allowed provided total bilirubin is \< 3.5 mg/dL AND direct bilirubin is normal * No acute or known chronic liver disease (e.g., chronic active hepatitis or cirrhosis) * Hepatitis C infection with minimal or no fibrosis on liver biopsy allowed Renal * Creatinine ≤ 1.5 mg/dL OR * Creatinine clearance \> 60 mL/min Cardiovascular * No New York Heart Association class III or IV cardiac disease * No congestive heart failure * No myocardial infarction withi…