title: [Retrospective analysis of the clinical course of 12 children given the diagnosis essential thrombocythemia].
abstract: BACKGROUND
  Essential Thrombocythemia (ET) is an acquired myeloproliferative disorder (MPD) characterized by excessive production of platelets. The disorder is usually affecting adults and is rarely diagnosed in children.
  
  
  METHODS
  In this retrospective study we describe 12 children aged 5-16 years in whom ET was presumed.
  
  
  RESULTS
  Median follow-up was 59 months (range 10-72). At diagnosis 7 patients had clinical symptoms (syncope, poor concentration, fatigue, abdominal pain and mild bleeding), 5 patients were diagnosed accidentally (operation, allergy, enuresis, pneumonia, routine examination). Median platelet count at diagnosis was 1 325 x 10 (9)/L (range 600-3 050). In 11 cases bone marrow morphology was consistent with ET, one patient had chronic idiopathic myelofibrosis. Cytogenetics were normal in all studied cases. Within 6 months after the initial presentation one patient who was diagnosed accidentally developed thrombosis, another patient had mild bleeding. 8 patients were treated with acetylsalicylic acid (in addition, 1 patient received hydroxyurea, 2 patients received anagrelide). On last follow-up all patients were alive, none had developed leukemia. 5 patients experienced hematological remission. 2 of these children had not received any therapy.
  
  
  CONCLUSIONS
  Many patients had symptoms attributable to ET. The clinical course is heterogeneous with complete normalization of platelets in the absence of cytoreductive therapy in some children. Due to the low incidence of ET in children indications for therapy are unclear and can only be deduced from findings obtained from studies in adults.
authors.affiliation: Zentrum für Kinderheilkunde und Jugendmedizin, Klinik IV: Pädiatrische Hämatologie/Onkologie, Universitätsklinikum Freiburg. kratz@kikli.ukil.uni-freiburg.de
authors.forename: C P
authors.initials: CP
authors.lastname: Kratz
authors.forename: A
authors.initials: A
authors.lastname: Abd El-Monheim
authors.forename: E M
authors.initials: EM
authors.lastname: Manke
authors.forename: M
authors.initials: M
authors.lastname: Rister
authors.forename: T
authors.initials: T
authors.lastname: Rogge
authors.forename: C M
authors.initials: CM
authors.lastname: Niemeyer
mesh_terms: D000293:Adolescent; D000367:Age Factors; D001856:Bone Marrow Examination; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009196:Myeloproliferative Disorders / Q000175:diagnosis / Q000628:therapy; D010976:Platelet Count; D012189:Retrospective Studies; D013920:Thrombocythemia, Essential / Q000175:diagnosis / Q000628:therapy; D013922:Thrombocytosis / Q000175:diagnosis / Q000628:therapy; D013997:Time Factors