| 1. Peripheral blood hypereosinophilia (eosinophil count ≥ 1.5 × 109/L and eosinophils ≥ 10% of white blood cells) |
| 2. Blasts constitute < 20% cells in peripheral blood and bone marrow, not meeting other diagnostic criteria for AML* |
| 3. No tyrosine kinase gene fusion including BCR::ABL1, other ABL1, PDGFRA, PDGFRB, FGFR1, JAK2, or FLT3 fusions |
| 4. Not meeting criteria for other well-defined MPN; chronic myelomonocytic leukemia, or SM† |
| 5. Bone marrow shows increased cellularity with dysplastic megakaryocytes with or without dysplastic features in other lineages and often significant fibrosis, associated with an eosinophilic infiltrate or increased blasts ≥ 5% in the bone marrow and/or ≥ 2% in the peripheral blood |
| 6. Demonstration of a clonal cytogenetic abnormality and/or somatic mutation(s)‡ |
| The diagnosis of CEL requires all 6 criteria. |
| 1. Peripheral blood hypereosinophilia (eosinophil count ≥ 1.5 × 109/L and eosinophils ≥ 10% of white blood cells) |
| 2. Blasts constitute < 20% cells in peripheral blood and bone marrow, not meeting other diagnostic criteria for AML* |
| 3. No tyrosine kinase gene fusion including BCR::ABL1, other ABL1, PDGFRA, PDGFRB, FGFR1, JAK2, or FLT3 fusions |
| 4. Not meeting criteria for other well-defined MPN; chronic myelomonocytic leukemia, or SM† |
| 5. Bone marrow shows increased cellularity with dysplastic megakaryocytes with or without dysplastic features in other lineages and often significant fibrosis, associated with an eosinophilic infiltrate or increased blasts ≥ 5% in the bone marrow and/or ≥ 2% in the peripheral blood |
| 6. Demonstration of a clonal cytogenetic abnormality and/or somatic mutation(s)‡ |
| The diagnosis of CEL requires all 6 criteria. |
AML with recurrent genetic abnormalities with < 20% blasts is excluded.
Eosinophila can be seen in association with SM. However, “true” CEL, NOS may occur as SM-AMN (SM with an associated myeloid malignancies).
In the absence of a clonal cytogenetic abnormality and/or somatic mutation(s) or increased blasts, bone marrow findings supportive of the diagnosis will suffice in the presence of persistent eosinophilia, provided other causes of eosinophilia having been excluded.