Acute myeloid leukaemia (AML) is a highly complex and heterogeneous disease. Proper classification according to the 2016 World Health Organization (WHO) classification requires a systematic approach and integration of key clinical, laboratory, pathologic and genetic information [1, 2]. Great advances in our understanding of the pathogenesis and molecular underpinnings of AML have been realized since the original AML classification using the French–American–British (FAB) system (1976). This genetic revolution not only contributes to enhanced disease diagnosis and prognostication but also to ongoing improvements in therapeutic strategies.

Myelodysplastic syndromes (MDS) comprise a heterogeneous group of myeloid neoplasms defined by peripheral cytopaenia, morphologic dysplasia in one or more haematopoietic lineages, and genetic instability with risk of transformation to acute myeloid leukaemia (AML). A diagnosis of MDS requires the presence of cytopaenia, plus one or more of the following diagnostic features: morphologic evidence of dysplasia in >10% of cells involving at least one haematopoietic lineage, increased blasts, and/or an MDS-defining cytogenetic abnormality. Modern diagnosis of MDS was standardized by the French–American–British (FAB) cooperative group in 1982, which included the first standard descriptions of myelodysplasia [1], and was further refined in the World Health Organization (WHO) classification of 2001, which more specifically quantified dysplasia (Table 8.1) [2].