The Forgotten Myeloproliferative Disorder: Myeloid Metaplasia

Abstract

Abstract Learning Objectives After completing this course, the reader will be able to: Derive a conceptual understanding of the classification as well as the pathogenesis of chronic myeloproliferative disorders with emphasis on myelofibrosis with myeloid metaplasia. Recognize how myelofibrosis with myeloid metaplasia is diagnosed and know what the differential diagnosis constitutes. Be familiar with current therapeutic options in myelofibrosis with myeloid metaplasia. Access and take the CME test online and receive one hour of AMA PRA category 1 credit at CME.TheOncologist.com Myelofibrosis with myeloid metaplasia is a hematologic disorder currently classified with polycythemia vera and essential thrombocythemia as a chronic myeloproliferative disease. The median age at diagnosis is 60 years, and more than 90% of patients are diagnosed after age 40 years. Clinical manifestations include massive splenomegaly, progressive anemia, profound constitutional symptoms, and extramedullary hematopoiesis. The diagnosis is confirmed by bone marrow examination after other causes of myelofibrosis are ruled out. Median survival is 5 years and causes of death include leukemic transformation. Prognosis is adversely affected by the presence of anemia (hemoglobin <10 g/dl), leukopenia or leukocytosis (white blood cells >30,000/μl), circulating blasts, and hypercatabolic symptoms. Conventional treatment is palliative and does not improve survival. In this regard, androgen preparations, corticosteroids, and erythropoietin are useful for the treatment of disease-associated anemia. Symptomatic splenomegaly is best managed by cytoreductive therapy or surgical removal. Radiation therapy is most useful in the treatment of nonhepatosplenic extramedullary hematopoiesis. New treatment approaches include the use of thalidomide alone or in combination with prednisone and hematopoietic stem cell transplantation.