Chronic neutrophilic leukemia other diagnostic studies

Sites of Involvement
Peripheral blood, bone marrow, spleen, and liver are most common, but any organ or tissue can be infiltrated by neutrophils.

Bone Marrow Biopsy
On both the bone marrow aspirate and the core biopsy, a hypercellular marrow with an increased myeloid:erythroid ratio of 20:1 or greater. Myelocytes and neutrophils are increased, and blasts and promyelocytes are not increased. Due to the myeloproliferative nature of the disease, an increase in megakaryocytes and erythroid precursors may be observed, but dyspoiesis in not seen in any cell lineage. Also, reticulin fibrosis is rare.

There is a reported association between CNL and multiple myeloma, so the bone marrow biopsy may show evidence of a plasma cell dyscrasia with increased numbers of atypical plasma cells.

Spleen
Splenic infiltrates are typically found only in the red pulp.

Liver
Hepatic infiltrates can be found in either the sinusoids, portal triad regions, or both.

Immunophenotype
No distinct immunophenotype abnormality for CNL has been described.

Genetics
The majority (90%) of cases have not had detectable cytogenetic abnormalities. Most importantly, the Philadelphia chromosome and other BCR/ABL fusion genes are not detected.