• Among 123 patients with ringed sideroblasts on bone marrow aspirates, 85 had acquired ringed sideroblasts with primary myelodysplasia. The patients were placed in categories modified from the French-American-British classification based on percentages of ringed sideroblasts and myeloblasts in the initial bone marrow. Overall, 48% (41/85) of patients with myelodysplasia developed acute leukemia. Primary acquired sideroblastic anemia was the most favorable category with longer survival and 13.8% (4/29) leukemic conversions. Variables correlating with leukemic transformation included male sex, thrombocytopenia, neutropenia, and pseudo—Pelger-Huët neutrophils. Only two variables had independent predictive value by multivariate regression analysis: a high percentage of myeloblasts and a low percentage of ringed sideroblasts. Numerous ringed sideroblasts strongly predicts a more favorable course in myelodysplastic patients.
(Arch Intern Med 1988;148:653-656)