[Morphologic diagnosis of myelodysplastic syndromes].

Although cytomorphologic evaluation is important for the diagnosis of myelodysplastic syndromes (MDS), a standardized approach is still lacking. According to the World Health Organization classification, the minimum percentage of cells manifesting dysplasia required to qualify as significant is ≥10% in one or more hematopoietic cell lineages. However, the suitability of this threshold (10%) has not been fully assessed in each lineage. Definitions of the various dysplastic forms that are important for the diagnosis of MDS are still lacking. Morphologic definitions of dysplastic forms have been proposed by the International Working Group on Morphology of MDS (IWGM-MDS). For the diagnosis of MDS, morphologic dysplastic changes should be classified into two categories: those with highly specific forms and those with less specific forms. Quantitative morphologic evaluations that include the specificity of the dysplastic forms have been reported by the "National Research Group on Idiopathic Bone Marrow Failure Syndromes, Japan" and "Rete Ematologica Lombarda (REL) clinical network."