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 within the past 6 months Other * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective barrier contraception during and for 3 months after study participation * No concurrent active opportunistic infection * No other severe and/or life-threatening medical disease * No other malignancy within the past 5 years except clinically insignificant malignancy not requiring active intervention, basal cell skin cancer, or carcinoma in situ of the cervix PRIOR CONCURRENT THERAPY: Biologic therapy * More than 4 weeks since prior biologic therapy for KS * More than 2 weeks since prior granulocyte colony-stimulating factor * No concurrent biologic agents for KS Chemotherapy * More than 4 weeks since prior chemotherapy for KS (6 weeks for nitrosoureas or mitomycin) * No concurrent chemotherapy for KS, including systemic cytotoxic chemotherapy Endocrine therapy * No concurrent systemic corticosteroid therapy except replacement doses Radiotherapy * See Disease Characteristics * More than 4 weeks since prior radiotherapy for KS * No concurrent radiotherapy for KS Surgery * More than 2 weeks since prior major surgery Other * No prior imatinib mesylate * More than 60 days since prior local therapy to any KS indicator lesion unless the lesion has progressed since treatment * More than 4 weeks since prior investigational therapy for KS * More than 4 weeks since other prior therapy for KS * More than 14 days since prior acute treatment for an infection or other serious medical illness * No concurrent warfarin * No concurrent grapefruit juice * No other concurrent therapy for KS * No other concurrent investigational drugs * Concurrent antiretroviral therapy required except for patients who have exhausted all available treatment options