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9 - Grade/differentiation unknown, not stated, or not applicable
Early essential thrombocythemia
Essential hemorrhagic thrombocythemia
Idiopathic hemorrhagic thrombocythemia
Essential thrombocythemia is a clonal myeloproliferative neoplasm. Rare chronic blood disorder characterized by elevated platelet count. Sustained thrombocytosis in blood and increased numbers of large, mature megakaryocytes in bone marrow; clinically episodes of thrombosis and/or hemorrhage.
A diagnosis of "post essential thrombocythemia myelofibrosis" is a progression of essential thrombocythemia and would be the same primary.
The diagnosis is clinical (diagnosis of exclusion); the physician diagnoses this disease by excluding other myeloproliferative neoplasms and correlating those equivocal results with the patient's symptoms. Bone marrow and blood are the principle sites of involvement. The spleen does not show significant extramedullary hematopoiesis but is a sequestration site for platelets. In some cases this disorder may be progressive, and only rarely evolves into acute myeloidleukemia or myelofibrosis.