Case of chronic‐phase chronic myelogenous leukemia with an abdominal hematopoietic tumor of leukemic clone origin

We report a 59‐year‐old man with chronic myelogenous leukemia (CML) in chronic phase who presented with a large abdominal tumor. Biopsy revealed proliferation of granulocytic‐, erythroid‐, and megakaryocytic‐lineage cells in a retroperitoneal lymph node. The BCR/ABL fusion gene was detected on a paraffin‐embedded tissue section of the lymph node by double‐color fluorescence in situ hybridization, indicating an extramedullary hematopoietic tumor of CML origin. This patient has achieved a complete cytogenetic response for 19 months with imatinib mesylate (STI571; Gleevec), in association with the regression of the tumor. However, the development of an extramedullary tumor in chronic‐phase CML generally indicates a poor prognosis, because it commonly consists of blast proliferation and is followed by blast crisis in the marrow within a few months. This case, therefore, points to the importance of histological examination of extramedullary tumors in CML for evaluation of disease status and for therapeutic decisions. Am. J. Hematol. 77:167–170, 2004. © 2004 Wiley‐Liss, Inc.