The nosology of myelodysplastic syndromes

A recent letter by Lichtman1 discusses very eloquently the pitfalls, inconsistencies, and illogicalities of the current nosology of clonal myeloid diseases. Dr Lichtman argues that the terms refractory anemia and myelodysplasia should be made obsolete because they are misnomers and exhorts the hematology community to take up the challenge of rectifying this flawed, albeit World Health Organization–approved, nomenclature. He has also made suggestions for a revised classification of myelodysplastic syndromes in one of his recent articles.2 

Although Dr Lichtman's arguments are very sound and valid, his suggestions2 for a revised terminology of “refractory anemias” and “myelodysplastic syndromes” are, unfortunately, far from satisfactory. His proposal for a revised classification of myeloid neoplasms is based on the following categorizations: minimal- to moderate-deviation clonal myeloid disorders, ineffective erythropoiesis (precursor apoptosis) is prominent, overproduction of cells is prominent, moderately severe–deviation clonal myeloid disorders, severe-deviation clonal myeloid disorders, and very severe–deviation clonal myeloid disorders.

In my opinion, the above approach is, although based on a rational pathophysiologic basis, not particularly suited for day-to-day clinical use. I would like to put forward another suggestion for a revised nosology of myeloid neoplasms (Table 1). This proposed nomenclature would have a number of advantages, compared with the current classification of myelodysplastic syndromes or the one suggested by Dr Lichtman. First, it would accurately identify the conditions included as “clonal diseases,” thus rectifying the single most important drawback of the currently used classification. Second, it would provide information about the pathologic/clinical progression of the underlying disease, analogous to those classifications successfully used for several nonhematologic neoplastic diseases. Third, unlike the current system of terminology of myelodysplastic disorders that appears to give an impression that the primary pathology lies in the erythroid lineage due to the usage of terms “refractory anemia,” “refractory anemia with excess blasts,” and so forth, the proposed classification would not give that erroneous impression. Finally and perhaps most importantly, this system would be very simple, uncomplicated, and comprehensible to nonhematologists and patients. For these reasons, I believe that this proposal deserves consideration.