Refractory anemia and the myelodysplastic syndromes.

Refractory anemia is a component of each of the myelodysplastic syndromes (MDSs). MDSs are acquired pluripotent stem cell disorders leading to one or more peripheral blood cytopenias with dysplasia in the peripheral blood and bone marrow. MDS and aplastic anemia are sometimes grouped as bone marrow failure disorders because patients present with similar peripheral blood pictures. The bone marrow in MDS is generally hypercellular, due to ineffective hematopoiesis, in contrast to the hypocellular bone marrow of aplastic anemia. MDS is more common in the elderly, differing from aplastic anemia that affects all ages. The characteristics of each of the subgroups of the MDS using the World Health Organization (WHO) classification are described. Cytogenetic analysis provides a useful part of disease diagnosis in this new classification system. There is no successful treatment for MDS other than hematopoietic stem cell transplantation which is usually recommended for patients under age 50. A prognostic scoring system has been developed to help predict the severity of disease and guide treatment. Approximately 10% to 40% of MDS cases terminate in acute leukemia. Current treatment consists mostly of supportive measures; however several new therapies are being explored.