SUCCESSFUL TREATMENT OF ESSENTIAL THROMBOCYTHEMIA EVOLVING INTO AGNOGENIC MYELOID METAPLASIA WITH INTERFERON-ALPHA

Purpose: Essential thrombocythemia and agnogenic myeloid metaplasia as one form of idiopathic myelofibrosis are myeloproliferative disorders and are quite rare in children. A patient with essential thrombocythe mia that transformed to ''adult-type'' agnogenic myeloid metaplasia is described. Patients and Methods: A routine examination of an 8-year-o ld girl with bronchial asthma showed thrombocytosis. Essential thrombo cythemia was diagnosed 2 years later. During a 3-year follow-up withou t treatment, transition of the essential thrombocythemia to agnogenic myeloid metaplasia was noticed. The patient had an excellent response to interferon (IFN)-alpha therapy. Conclusion: This case is unique bec ause of the availability of premorbid hematologic data and the natural progression of essential thrombocythemia to agnogenic myeloid metapla sia. Whether IFN-alpha therapy can prevent the progression of idiopath ic myelofibrosis to leukemia has not yet been determined.