Patients will first be evaluated for inclusion in the extension phase of the study at either the follow-up visit following three month withdrawal from Gleevec treatment or at the visit after the follow-up visit. Patients can undergo evaluation for inclusion in the extension phase up to six months following their completion of the initial one year trial. All patients evaluated for inclusion in the extension phase will sign a new informed consent form detailing the purpose and procedures associated with the extension phase at the initial visit. After the initial visit, patients who meet inclusion criteria will be required to undergo evaluation every three months for the 27 months following initiation of treatment, or more frequently if deemed clinically necessary. Treatment will consist of Gleevec, at doses ranging from 100 to 400 mg daily (100 mg pills will be distributed for oral administration). At each study visit, a history and physical exam will be performed and urine and blood tests will be conducted for disease activity and organ function. Additional blood for research may also be collected at study visits. The Modified Rodnan Skin Score will be measured to assess the degree of skin involvement associated with the patient's disease. Patients will also continue to complete questionnaires about their ability to function and quality of life.