hematology and oncology
Essential Thrombocythemia
Diagnosis of Essential Thrombocythemia
Complete blood count (CBC) and peripheral blood smear Exclusion of causes of secondary thrombocytosis and other myeloproliferative neoplasms Cytogenetic studies JAK2mutation and, if negative,CALRorMPLmutation analysis Rarely, bone marrow aspirate and biopsy Essential thrombocythemia is a diagnosis of exclusion and should be considered in patients in whom common reactive causes of Reactive Thrombocytosis (Secondary Thrombocythemia) and other myeloproliferative neoplasms are excluded. If essential thrombocythemia is suspected, complete blood count (CBC), peripheral blood smear, and (because thrombocytosis can be caused by iron deficiency) iron studies should be done . In essential thrombocythemia, the platelet count is > 450,000/mcL (>450×109/L), but can be>1,000,000/mcL (>1000×109/L). The platelet count may decrease during pregnancy. The diagnosis is suggested by normal hematocrit, white blood cell count, mean corpuscular volume (MCV), and iron studies, as well as absence of theBCR-ABLtranslocation. The peripheral smear may show giant platelets and megakaryocyte fragments. Some Myelodysplastic Syndrome (MDS) (eg, refractory anemia with ringed sideroblasts and thrombocytosis [RARS-T], and the 5q- syndrome) may present with an elevated platelet count. If cytopenias are identified, a assay to exclude Chronic Myeloid Leukemia (CML) (CML, which can manifest with thrombocytosis alone). If the 50% suggests Polycythemia Vera or World Health Organization guidelines suggest that a bone marrow biopsy showing increased numbers of enlarged, mature megakaryocytes is required for a diagnosis of essential thrombocythemia, but this criterion has never been validated prospectively, and a marrow examination will not distinguish essential thrombocythemia from polycythemia vera ( Diagnosis reference ). The allele burden is usually >50% in polycythemia vera and primary myelofibrosis. 1.Barbui T, Thiele J, Gisslinger H, et al. The 2016 WHO classification and diagnostic criteria for myeloproliferative neoplasms: document summary and in-depth discussion.Blood Cancer J2018; 8(2):15. doi:10.1038/s41408-018-0054- 