Features of essential thrombocythaemia in childhood: a study of five children

Essential thrombocythaemia (ET) is usually considered a disease of the midd le-aged but, with the advent of automated platelet counting, ET is diagnose d with increasing frequency in young adults and, even more rarely in childr en. We report ave paediatric patients (four girls and one bog: mean age 89 months) diagnosed with ET in agreement with Polycythaemia Vera Study Group criteria, The patients had a persistent thrombocytosis over 900 x 10(9)/l a nd, at the time of diagnosis, their platelet count ranged between 1112 and 3178 x 10(9)/l, A 9-month-old girl had thrombosis of the inferior cava vein , two children had headaches and two others remained asymptomatic throughou t the follow-up period. Megakaryocytes in the bone marrow were increased in number, The chromosomal analysis was normal, and bcr rearrangement was alw ays negative, None of the patients had spontaneous BFU-E or altered levels of serum crythropoietin and thrombopoietin. Two patients showed alteration of platelet aggregation, and all had decreased levels of intraplatelet sero tonin, In spite of the diagnosis of ET in our patients, we are not sure tha t the cases reported here are really myeloproliferative disorders, The feat ures could suggest that the cases observed may be affected by art idiopathi c thrombocytosis' without myeloproliferation, Possible variants of ET are d escribed in young adults, and the heterogeneous nature of BT is also sugges ted by our paediatric patients, Only careful long-term follow-up of patient s such as these will clarify the natural history of these disorders and sug gest therapeutic management.