What Is “WHO“? Myelodysplastic Syndromes Classification

In the decade of new therapeutic options for myelodysplastic syndromes (MDS), it is more important than ever to recognize how to diagnose the disease and classify the patients into a subtype or risk stratification that allows predicting prognosis and, more importantly, developing treatment strategy accordingly. The classification of MDS has been an evolving process as we learn more about the disease. In this article, we review the World Health Organization (WHO) classification of MDS, highlighting the major changes compared with the French-American-British classification. We review the validation of the WHO and then discuss the application and difficulties of the WHO classification. We study the International Prognostic Scoring System and its new modification, the WHO prognostic scoring system. Finally, we look to the future, introducing some of the suggested revisions to the WHO classification.