Abstract

Imatinib mesylate (STI 571) is one of the fundamental chemotherapeutic agents used in the treatment of the chronic, accelerated and blastic phases of chronic myelocytic leukemia (CML), gastrointestinal stromal tumors and Philadelphia chromosome–positive acute lymphoblastic leukemia. It selectively inhibits receptor tyrosine kinases. Its effects limit the use of this drug. We present a case with a serious skin reaction requiring the discontinuation of the drug and that developed in relation to imatinib therapy. Six months prior, a 61-year-old male patient presenting to the hematology polyclinic with complaints of weight loss and sweating was hospitalized due to high leukocyte value. As a result of the hemogram, biochemistry analyses, peripheral blood smear examination, bone marrow aspiration evaluation, cytogenetic examination using FISH and PCR that were performed, CML was diagnosed. Additionally, to exclude myelofibrosis, we examined a bone marrow biopsy. Imatinib mesylate was started at 400 mg/day orally. In the fourth month of treatment, the patient complained of itching and a skin rash. Although the drug dose was reduced (300 mg/day), his complaints gradually increased. The skin biopsy result was superficial perivascular dermatitis. Imatinib was discontinued, and the patient was started on corticosteroid. The lesions disappeared completely. A month later, the patient was restarted on imatinib mesylate. However, the lesions recurred more prominently. His itching increased. The patient was considered intolerant to imatinib mesylate, and a second-generation tyrosine kinase inhibitor, dasatinib 100 mg/day, was started orally. The follow-up and treatment continues for the patient, who has been taking dasatinib 100 mg/day for the last two months without any skin finding or complaints. Imatinib mesylate–induced skin reactions are associated with the pharmacologic effect of the drug rather than hypersensitivity to the drug. Skin reactions are frequently observed, and this side effect is dose dependent. However, the interesting aspect of our case was that despite dose reduction, skin findings gradually increased, and eventually the drug had to be discontinued.