9962/3 Essential thrombocythemia


Essential hemorrhagic thrombocythaemia
Idiopathic hemorrhagic thrombocythaemia
Idiopathic thrombocythemia


Tumours of haematopoietic and lymphoid tissues
ICD-O-3 topography code: C42 and C77
ICD10: D47.3

/span>ssential thrombocythaemia (ET) is a chronic myeloproliferative neoplasm (MPN) that involves primarily the megakaryocytic lineage. It is characterized by sustained thrombocytosis ≥450x109/L in the peripheral blood (PB), increased numbers of large, mature megakaryocytes in the bone marrow (BM), and clinically by episodes of thrombosis and/or haemorrhage. Because there is no known genetic or biological marker specific for ET, other causes for thrombocytosis must be excluded, including other MPN, inflammatory and ?infectious disorders, haemorrhage and other types of haematopoietic and non-haematopoietic neoplasms. The presence of a BCR-ABL1 fusion gene excludes the diagnosis of ET. The diagnostic criteria are outlined in Table 2.06