Acute myeloid leukemia and myelofibrosis: Simultaneous transformation of essential thrombocythemia during treatment with hydroxyurea.

Essential thrombocytosis (ET) is usually an indolent disease but can uncommonly evolve into acute myeloid leukemia (AML) with a grim prognosis of 2-7 months. Studies report a lower incidence of leukemic transformation when compared to fibrotic transformation. The risk of transformation depends on the age, duration of disease, and tumor biology. Hydroxyurea, a cytoreductive agent, is generally associated with minimal adverse reactions; however, there are conflicting data on its effect on leukogenecity. We describe a rare case of a 79-year-old female developing disseminated intravascular coagulation due to the transformation of ET to both AML and myelofibrosis while being treated with hydroxyurea for 8 years.