Imatinib Mesylate Induced Gastric B-Cell Lymphoma

Abstract

Purpose: Imatinib mesylate is a common first-line treatment for chronic myelogenous leukemia (CML). We present the first case, to our knowledge, of a CML patient treated with imatinib mesylate who developed gastric lymphoma. A 53-year-old man with a history of CML was taking imatinib mesylate with confirmed hematological and cytogenetic remission. However, the patient developed diffuse abdominal pain with associated bloody stools. A colonoscopy done 5-years previously showed only hemorrhoids and a benign colon polyp. An esophagogastroduodenoscopy (EGD) done during the same time showed gastric erythema and erosive duodenitis. A new outpatient EGD showed a large, fungating, non-circumferential mass at the incisura (Figure A). The patient had a laparoscopic abdominal exploration which showed a large gastric mass in the body of the stomach, extending into the antrum midway between the lesser and greater curvature. The mass was not removed surgically. In situ staining for Epstein Barr Virus (EBV) confirmed high-grade Burkitt's gastric lymphoma. Fluorescence in situ hybridization (FISH) of the biopsy revealed a genetically distinct neoplasm from CML. Imatinib mesylate was stopped and he received a different chemotherapy regimen for two courses. Follow-up EGD two months later showed only a large gastric ulcer at incisura angularis (Figure B); the mass dramatically decreased in size. Imatinib mesylate, a tyrosine kinase inhibitor, is a first-line chemotherapy agent used in the treatment of CML. It acts to inhibit the tyrosine kinase activity of this disease. The development of a de novo lymphoma and cutaneous EBV-positive B-cell lymphoproliferative disease in CML patients treated by imatinib have been reported, but it is very uncommon. In this case, the EBV gastric lymphoma occurred during imatinib treatment and resolved significantly after stopping treatment; it is thought the modulation of T-cell function by imatinib was the fulcrum point in the development of EBV-gastric lymphoma. In addition, the CML showed genetic and hematological remission, so the concern of a blast crisis forming was mitigated. To our knowledge, this is the first report of gastrointestinal Burkitt's lymphoma development after prolonged treatment with imatinib mesylate and is an important complication of therapy in CML.Figure A: Burkitt's lymphoma seen in stomach Figure B. Reduction of Burkitt's lymphoma in stomach.