LAUSR

Due to the lack of specific clinical and biological features, M6a-acute erythroid leukemia (M6a-AEL), defined as an erythroid/myeloid type of acute leukemia, is no longer a distinct entity in the last classification of myeloid neoplasms by the World Health Organization (WHO).1 The diagnosis of M6a-AEL was previously made if a proliferation of erythroid precursors 50% with a myeloblast count 20% when counted as a percentage of non-erythroid cells, was found in the bone marrow.2 In 2016, revision of the WHO classification, the denominator used for calculating the blasts percentage was changed from non-erythroid cells to all nucleated cells. Consequently, M6a-AELs are now either myelodysplastic syndromes (MDSs) if the percentage of myeloblasts is 20% of non-erythroid cells but <20% of all nucleated cells or acute myeloid leukemia (AML) if the percentage of myeloblasts is 20% of all nucleated cells. As for any other AMLs prior therapy, recurring WHO cytogenetic abnormalities, and criteria for AML with myelodysplasia-related changes (AML-MRC) have to be taken into consideration for classification.