Megakaryoblastic transformation of chronic myelogenous leukemia.

A 52-year-old man with Ph1-positive chronic myelogenous leukemia (CML) developed a blastic transformation in which the predominant cell type micromegakaryocytes. He did not respond to treatment. A review of the 15 previously reported cases of patients with circulating megakaryocyte abnormalities in association with either CML or a Ph1 chromosome positive myeloproliferative disorder suggests a female predominance rather than the usual male predominance of CML. Survival of the six patients reported as megakaryoblastic transformation of CML as well as this patient was poor.