Table 6.

Diagnostic criteria for chronic neutrophilic leukemia (CNL)


1. Peripheral blood white blood cell count ≥ 13 × 109/L* Segmented neutrophils plus banded neutrophils constitute ≥ 80% of the white blood cells. No significant dysgranulopoiesis. Neutrophil precursors (promyelocytes, myelocytes, and metamyelocytes) constitute < 10% of the white blood cells. Circulating blasts only rarely observed. Monocyte count < 10% of all leukocytes.† 

2. Hypercellular bone marrow with neutrophil granulocytes increased in percentage and absolute number, showing normal maturation. 

3. CSF3R T618I or another activating CSF3R mutation or persistent neutrophilia (≥3 mo), splenomegaly, and no identifiable cause of reactive neutrophilia including absence of a plasma cell neoplasm or, if a plasma cell neoplasm is present, demonstration of clonality of myeloid cells by cytogenetic or molecular studies. 

4. Not meeting diagnostic criteria for BCR::ABL1-positive CML, PV, ET, PMF or of a myeloid/lymphoid neoplasms with eosinophilia and tyrosine kinase gene fusions. 

1. Peripheral blood white blood cell count ≥ 13 × 109/L* Segmented neutrophils plus banded neutrophils constitute ≥ 80% of the white blood cells. No significant dysgranulopoiesis. Neutrophil precursors (promyelocytes, myelocytes, and metamyelocytes) constitute < 10% of the white blood cells. Circulating blasts only rarely observed. Monocyte count < 10% of all leukocytes.† 

2. Hypercellular bone marrow with neutrophil granulocytes increased in percentage and absolute number, showing normal maturation. 

3. CSF3R T618I or another activating CSF3R mutation or persistent neutrophilia (≥3 mo), splenomegaly, and no identifiable cause of reactive neutrophilia including absence of a plasma cell neoplasm or, if a plasma cell neoplasm is present, demonstration of clonality of myeloid cells by cytogenetic or molecular studies. 

4. Not meeting diagnostic criteria for BCR::ABL1-positive CML, PV, ET, PMF or of a myeloid/lymphoid neoplasms with eosinophilia and tyrosine kinase gene fusions. 
*

At least 25 × 109/L in cases lacking CSF3R T618I or another activating CSF3R mutation.

†

Ten percent to 19% blasts in peripheral blood or bone marrow represent CNL in accelerated phase; ≥ 20% blasts represents blast phase.

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