Sideroblastic anemia terminating in myelofibrosis

Two patients with primary acquired sideroblastic anemia who eventually developed myelofibrosis with myeloid metaplasia are reported. Splenectomy was performed in one patient because of increasing blood transfusion requirements, and splenic histology revealed both myeloid metaplasia and ringed sideroblasts. The second patient showed a partial response of the sideroblastic anemia to pyridoxine therapy during the early stages of development of the myelofibrosis. Myelofibrosis with myeloid metaplasia may represent a nonspecific response of the marrow tissue to sideroblastic anemia as to other primary hematologic disorders.