[Treatment of essential thrombocythemia].

Essential thrombocythemia is a chronic myeloproliferative neoplasm characterized by sustained thrombocytosis, bone marrow megakaryocytic hyperplasia and an increased risk of thrombosis and hemorrhage. The goal of treatment is to prevent the development of vascular complications without increasing the risk of transformation. Patients aged>60 years or a history of thrombosis have a high risk of thrombosis while those with a platelet count>1,500 x 10(9)/l have a higher risk of hemorrhage. Patients with low-risk essential thrombocythemia can be managed appropriately with low-dose of acetylsalicylic acid or even observation only, while patients with a high-risk disease are candidates to receive cytoreductive treatment, hydroxyurea being the first choice therapy. Anagrelide is the most suitable option for patients with resistance or intolerance to hydroxyurea. All patients must be submitted to a rigorous control of cardiovascular risk factors.