Diagnostic criteria for chronic neutrophilic leukemia32,33
| Feature . | Diagnostic requirements . |
|---|---|
| Peripheral blood counts | Total WBC count ≥13/≥ 25 × 109/La Segmented and band neutrophils ≥80% of WBCs Myelocytes, metamyelocytes, and promyelocytes <10% of WBCs Monocytes <10% of WBCs Circulating blasts are rare or absent |
| Morphology | Absence of significant dysgranulopoiesis Hypercellular bone marrow with increased myeloid:erythroid ratio and intact granulocytic maturation |
| Genetics | Activating CSF3R mutationb |
| Exclusions | No BCR::ABL1 rearrangement or rearrangement associated with myeloid/lymphoid neoplasms with eosinophilia and TK gene fusions Not meeting criteria for PV, ET, or PMF |
| Feature . | Diagnostic requirements . |
|---|---|
| Peripheral blood counts | Total WBC count ≥13/≥ 25 × 109/La Segmented and band neutrophils ≥80% of WBCs Myelocytes, metamyelocytes, and promyelocytes <10% of WBCs Monocytes <10% of WBCs Circulating blasts are rare or absent |
| Morphology | Absence of significant dysgranulopoiesis Hypercellular bone marrow with increased myeloid:erythroid ratio and intact granulocytic maturation |
| Genetics | Activating CSF3R mutationb |
| Exclusions | No BCR::ABL1 rearrangement or rearrangement associated with myeloid/lymphoid neoplasms with eosinophilia and TK gene fusions Not meeting criteria for PV, ET, or PMF |
WHO fifth edition classification requires a minimal WBC of 25 × 109/L in all cases, while ICC allows a WBC ≥13 × 109/L in the presence of an activating CSF3R mutation.
In the absence of an activating CSF3R mutation, the neutrophilia must be persistent (≥3 months) and without an identifiable cause, and splenomegaly must be present.