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Advances in Hematology
Volume 2013 (2013), Article ID 309637, 11 pages
Review Article

Acquired Myelodysplasia or Myelodysplastic Syndrome: Clearing the Fog

1Professor of Clinical Medicine, Weill-Cornell Medical School and Director, Transitional Residency Program, Houston Methodist Hospital, 6550 Fannin Street, Suite 1001, Houston, TX 77030, USA
2Summit Toxicology, LLP, 1944 Cedaridge Circle, Superior, CO 80026, USA
3Schools of Pharmacy and Public Health, The University of Colorado, Denver, CO 80026, USA

Received 24 June 2013; Accepted 28 August 2013

Academic Editor: Giuseppe G. Saglio

Copyright © 2013 Ethan A. Natelson and David Pyatt. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Myelodysplastic syndromes (MDS) are clonal myeloid disorders characterized by progressive peripheral blood cytopenias associated with ineffective myelopoiesis. They are typically considered neoplasms because of frequent genetic aberrations and patient-limited survival with progression to acute myeloid leukemia (AML) or death related to the consequences of bone marrow failure including infection, hemorrhage, and iron overload. A progression to AML has always been recognized among the myeloproliferative disorders (MPD) but occurs only rarely among those with essential thrombocythemia (ET). Yet, the World Health Organization (WHO) has chosen to apply the designation myeloproliferative neoplasms (MPN), for all MPD but has not similarly recommended that all MDS become the myelodysplastic neoplasms (MDN). This apparent dichotomy may reflect the extremely diverse nature of MDS. Moreover, the term MDS is occasionally inappropriately applied to hematologic disorders associated with acquired morphologic myelodysplastic features which may rather represent potentially reversible hematological responses to immune-mediated factors, nutritional deficiency states, and disordered myelopoietic responses to various pharmaceutical, herbal, or other potentially myelotoxic compounds. We emphasize the clinical settings, and the histopathologic features, of such AMD that should trigger a search for a reversible underlying condition that may be nonneoplastic and not MDS.