Chronic neutrophilic leukemia: a contemporary review

Chronic neutrophilic leukemia (CNL) is recognized as a distinct clinicopathologic entity characterized by sustained mature neutrophilic leukocytosis splenomegaly with bone marrow granulocytic hyperplasia without evidence of dysplasia or striking reticulin fibrosis. This diagnosis is contingent on thorough initial investigation and follow-up to exclude underlying causes of reactive neutrophilia, particularly if evidence of myeloid clonality is lacking. The optimal therapy for CNL remains uncertain. Current management decisions are based on anecdotal reports or extrapolated from therapeutic strategies effective in similar chronic clonal myeloid disorders. Because of the potential for blastic transformation and progressive refractory neutrophilia, allogeneic stem cell transplantation may be appropriate for younger patients. Continued reporting of all cases of CNL and responses to therapeutic strategies must be encouraged.