Acute myeloid leukemia with myelodysplasia-related changes (AML-MRC) is a heterogeneous disorder defined by morphologic, genetic, or clinical features. Genetic abnormalities associated with AML-MRC are often associated with adverse prognostic features, and many cases are preceded by a myelodysplastic syndrome (MDS) or a myelodysplastic/myeloproliferative neoplasm.
Although the criteria of 20% or more blasts in blood or bone marrow and multilineage dysplasia affecting 50% or more of cells in two or more of the myeloid lineages seem straightforward for AML-MRC, identification of morphologic dysplasia among observers is not always consistent, and there is morphologic overlap with other leukemic disorders such as acute erythroleukemia.
Session 3 of the workshop cases displayed heterogeneity as expected within AML-MRC, yet several cases suggested that recently recognized entities may exist within this category, such as familial MDS/AML predisposition syndromes and rare cases of high-risk AML associated with the cryptic t(5;11)(q35;p15);NUP98-NSD1 that may masquerade as a del(5q). However, most cases of AML-MRC were usually associated with adverse genetic abnormalities, particularly -5/del(5q), -7/del(7q), and/or complex karyotypes.
Whole-genome sequencing and array studies may identify genetic abnormalities, such as those affecting TP53, which may provide prognostic information.