Diagnostic approach to myeloid neoplasms when erythroid precursors comprise ≥50% of BM nucleated cells
| BM erythroid precursors . | Myeloblast % of all cells in BM (or PB) . | Prior therapy? . | Recurring WHO genetic abnormality? . | Meets criteria for AML-MRC? . | Fourth edition diagnosis . | Updated fourth edition diagnosis . |
|---|---|---|---|---|---|---|
| ≥50% | NA | Yes | NA | NA | Therapy-related myeloid neoplasm | Therapy-related myeloid neoplasm |
| ≥50% | ≥20% | No | Yes | NA | AML with recurring genetic abnormality | AML with recurring genetic abnormality |
| ≥50% | ≥20% | No | No | Yes | AML with myelodysplasia-related changes | AML with myelodysplasia-related changes |
| ≥50% | ≥20% | No | No | No | AML, NOS, acute erythroid leukemia (erythroid/myeloid type) | AML, NOS (non erythroid subtype) |
| ≥50% | <20%, but ≥20% of nonerythroid cells | No | No* | NA | AML, NOS, acute erythroid leukemia (erythroid/myeloid subtype) | MDS† |
| ≥50% | <20%, and <20% of nonerythroid cells | No | No* | NA | MDS† | MDS† |
| >80% immature erythroid precursors with ≥30% proerythroblasts | <20% | No | No* | NA | AML, NOS, acute erythroid leukemia (pure erythroid type) | AML, NOS, acute erythroid leukemia (pure erythroid type) |
| BM erythroid precursors . | Myeloblast % of all cells in BM (or PB) . | Prior therapy? . | Recurring WHO genetic abnormality? . | Meets criteria for AML-MRC? . | Fourth edition diagnosis . | Updated fourth edition diagnosis . |
|---|---|---|---|---|---|---|
| ≥50% | NA | Yes | NA | NA | Therapy-related myeloid neoplasm | Therapy-related myeloid neoplasm |
| ≥50% | ≥20% | No | Yes | NA | AML with recurring genetic abnormality | AML with recurring genetic abnormality |
| ≥50% | ≥20% | No | No | Yes | AML with myelodysplasia-related changes | AML with myelodysplasia-related changes |
| ≥50% | ≥20% | No | No | No | AML, NOS, acute erythroid leukemia (erythroid/myeloid type) | AML, NOS (non erythroid subtype) |
| ≥50% | <20%, but ≥20% of nonerythroid cells | No | No* | NA | AML, NOS, acute erythroid leukemia (erythroid/myeloid subtype) | MDS† |
| ≥50% | <20%, and <20% of nonerythroid cells | No | No* | NA | MDS† | MDS† |
| >80% immature erythroid precursors with ≥30% proerythroblasts | <20% | No | No* | NA | AML, 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.