CHAPTER 7: The Diagnosis of Myelodysplastic Syndromes

Myelodysplastic syndrome (MDS) is a clonal haematopoietic stem‐cell disorder, characterised by peripheral blood cytopenias and a risk of progression to acute myeloid leukaemia. Diagnosis is made primarily on the basis of dysplastic morphology affecting at least 10% of cells in one or more myeloid lineage, following the exclusion of causes of nonclonal dysplasia. Cytogenetic and immunophenotyping data provide supporting evidence of the presence of a clonal abnormality and prognostic information. Whilst the current WHO classification is based on morphological features, increased understanding of the pathophysiology of myelodysplastic syndromes gained from molecular techniques is likely to see their increased use as diagnostic tools and incorporation into future revised classifications.