RT Book, Section A1 Kaushansky, Kenneth A2 Kaushansky, Kenneth A2 Prchal, Josef T. A2 Burns, Linda J. A2 Lichtman, Marshall A. A2 Levi, Marcel A2 Linch, David C. SR Print(0) ID 1180472815 T1 Essential Thrombocythemia T2 Williams Hematology, 10e YR 2021 FD 2021 PB McGraw-Hill Education PP New York, NY SN 9781260464122 LK hemonc.mhmedical.com/content.aspx?aid=1180472815 RD 2024/03/28 AB SUMMARYEssential thrombocythemia is a clonal stem cell disorder characterized by an overproduction of platelets, and is most commonly associated with mutations in one of three genes, JAK2, CALR, or C-MPL, although a fraction of patients termed “triple negative” carry wild-type alleles at these three loci*. Complications include thrombosis, hemorrhage, and progression to myelofibrosis or acute myeloid leukemia. Diagnosis requires exclusion of reactive thrombocytosis and other myeloid malignancies associated with an elevated platelet count. Therapy, when appropriate, is aimed at reducing thrombotic complications and includes modification of known cardiovascular risk factors and antiplatelet therapy for the majority of such patients. Those at high risk of thrombosis are also considered for cytoreductive therapy with agents such as hydroxyurea, anagrelide, or interferon-α. Although the majority of patients can expect to live for many years, mortality rates are increased compared with the general population as a consequence of disease complications.