Imatinib in Patients With Mucosal or Acral/Lentiginous Melanoma

Inclusion Criteria: * Melanomas that arise on chronically sun damaged skin and have pathologic evidence of solar elastosis * History of primary mucosal or acral/lentiginous melanoma * Histologically documented stage IV metastatic melanoma * ECOG performance status 0,1, or 2 * Estimated life expectancy of 6 months or greater * Age 18 years or older * Creatinine \< 1.5 x ULN * ANC \> 1500 ul * Platelets \> 100,000 ul * Total bilirubin, AST, and ALT \< 2 x ULN * Amylase and lipase \< 1.5 x ULN * C-kit mutation documented from either primary or metastatic tumor site * \> 4 weeks from prior chemotherapy or investigational drug * At least one measurable site of disease as defined by at least 1 cm in greatest dimension Exclusion Criteria: * Severe and/or uncontrolled medical disease * Pregnant or nursing mothers * Any other significant medical, surgical, or psychiatric condition that my interfere with compliance * Patient is \< 5 years free of another primary malignancy except: basal cell skin cancer or a cervical carcinoma in situ * Concurrent treatment with Warfarin * Prior treatment with c-kit inhibitor * Patient with Grade III/IV cardiac problems as defined by NYHA criteria * No H2 blockers or proton pump inhibitors * Known brain metastasis * Known chronic liver disease * Known diagnosis of HIV infection * Previous radiotherapy to \> 25% of the bone marrow * Major surgery within 2 weeks prior to study entry * Patient has received any other investigational agent within 28 days of first study drug dosing * Chemotherapy within 4 weeks prior to study entry