Table 16

Diagnostic approach to myeloid neoplasms when erythroid precursors comprise ≥50% of BM nucleated cells

BM erythroid precursorsMyeloblast % of all cells in BM (or PB)Prior therapy?Recurring WHO genetic abnormality?Meets criteria for AML-MRC?Fourth edition diagnosisUpdated fourth edition diagnosis
≥50%NAYesNANATherapy-related myeloid neoplasmTherapy-related myeloid neoplasm
≥50%≥20%NoYesNAAML with recurring genetic abnormalityAML with recurring genetic abnormality
≥50%≥20%NoNoYesAML with myelodysplasia-related changesAML with myelodysplasia-related changes
≥50%≥20%NoNoNoAML, NOS, acute erythroid leukemia (erythroid/myeloid type)AML, NOS (non erythroid subtype)
≥50%<20%, but ≥20% of nonerythroid cellsNoNo*NAAML, NOS, acute erythroid leukemia (erythroid/myeloid subtype)MDS
≥50%<20%, and <20% of nonerythroid cellsNoNo*NAMDSMDS
>80% immature erythroid precursors with ≥30% proerythroblasts<20%NoNo*NAAML, NOS, acute erythroid leukemia (pure erythroid type)AML, NOS, acute erythroid leukemia (pure erythroid type)
  • AML-MRC, acute myeloid leukemia with myelodysplasia-related changes; NA, not applicable.

  • * Cases of AML t(8;21)(q22;q22.1);RUNX1-RUNX1T1, AML with inv(16)(p13.1q22) or t(16;16)(p13.1;q22);CBFB-MYH11 or APL with PML-RARA, may rarely occur in this setting with <20% blasts and those diagnoses would take precedence over a diagnosis of AML, NOS, or MDS.

  • Classify based on myeloblast percentage of all BM cells and of PB leukocytes and other MDS criteria.