Tehran University of Medical Sciences International Journal of Hematology-Oncology and Stem Cell Research 2008-2207 7 2 2013 06 15 34 36 Majid Vafaie Research Center of Thalassemia & Hemoglobinopathy, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. Kaveh Jaseb Research Center of Thalassemia & Hemoglobinopathy, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. Majid Ghanavat Research Center of Thalassemia & Hemoglobinopathy, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. Mohamad Pedram Research Center of Thalassemia & Hemoglobinopathy, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. Tooran Rahiminia Research Center of Thalassemia & Hemoglobinopathy, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. 2015 10 14 Essential thrombocythemia is a rare myeloproliferative disorder in pediatrics. This myeloproliferative disorder is charactherized by thrombocytosis and hyperplasia of megakaryocytes in the bone marrow. Other cell lines are not involved.JAK2V617Fmutations has been identified in approximately half the patients with this disorder. We describe a 12-year-old boy with essential throbocythemia. The patient had a persistent thrombocytosis over 600x109 /L and the time of diagnosis, his platelet count ranged between 900x109and 2150x109/L. Megakaryocytes in the bone marrow were increased in number. The chromosomal analysis was normal and bcr/abl rearrangement was negative. He remained asymptomatic throughout the follow-up period. https://ijhoscr.tums.ac.ir/index.php/ijhoscr/article/view/453 https://ijhoscr.tums.ac.ir/index.php/ijhoscr/article/download/453/344