A case of chronic myeloid leukemia with features of essential thrombocythemia in peripheral blood and bone marrow

Abstract

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm characterized by over-production of myeloid white blood cells. Philadelphia chromosome is an essential finding for CML diagnosis. Generally, a clinical diagnosis of essential thrombocythemia (ET) can be established from isolated marked thrombocytosis in peripheral blood. However, Philadelphia chromosome-positivity or bcr/abl rearrangement with isolated thrombocy-tosis should be diagnosed as CML, not ET, according to World Health Organization diag-nostic criteria. Therefore, CML should not be excluded before confirming the presence of the Philadelphia chromosome or bcr/abl rearrangement in cases of isolated thrombocy-tosis in peripheral blood. We report a case of CML with clinical features of ET in a patient successfully treated with imatinib.