Asymtomatic Essential Thrombocythemia in a Child: A Rare Case Report
We describe a 10 years old male with an incidental finding of an elevated platelet count. This patient had been admitted due to upper respiratory tract infection. His post medical history was unremarkable with a normal birth history and was taking no medications. Immunizations status was up to date. The platelet count at the time of referral was 950x109/L. The physical examination was normal with the exception of mild splenomegaly (just palpable splenomegaly). He had lower leg pain but deep vein thrombosis ruled out with color dupler ultrasonography. His parent platelet count was normal and there was no family history of thrombocytosis. His white blood cell count and differential count were unremarkable, and platelet size was not enlarged. Hb, ESR and C-reactive protein were all within normal ranges. Bone marrow examination was normocellular with relatively normal numbers and maturation of erythroid and myeloid lineages but show clusters of large megakaryocytes with increased hyperlobulated nuclei (). Myeloblasts are about 5% of all nucleated cells. Bone marrow biopsy show remarkable bony trabeculae and marrow spaces contain hematopoietic elements with predominance of large hyperlobulated megakaryocytes. Reticulin staining was negative for myelofibrosis. The overall histological features suggest chronic myeloproliferative disorder without myelofibrosis suggestive of ET. Cytogentic showed normal 46, XY karyotype. No bcr/abl chimaeric transcript was demonstrated by reverse transcription polymerase chain reaction. JAK2-V617F mutation was negative. Evaluation of the MPL W515L/K gene was negative in the patient. He received low dose aspirin (80mg/day). Her platelet count ranging from 303x109 to2131x109 /L. He was admitted to hospital because of anxiety and right lower leg pain. At this time his platelet count was 2131x109/L and we started hydroxyurea 1000mg and anagrelide 2mg for him. The mean platelet count was 1029x109/L. The platelet count has shown a trend of gradual fall over the past year and the latest platelet count was 580x109/L. He is asymptomatic now.