Chronic Neutrophilic Leukemia: A Case Report of Diagnosis in a 60-year-old Male

A BSTRACT Chronic neutrophilic leukemia (CNL) is an uncommon myeloproliferative neoplasm (MPN), characterized by determined neutrophilia, bone marrow hypercellularity, and hepatosplenomegaly. The BCR-ABL1 fusion gene is not obtained. A 60-year-old male complained of a black stool. The patient also complained of nausea, black vomiting, weakness, and joint pain. Anemic conjunctiva and splenomegaly were obtained. Laboratory tests showed hemoglobin 6.4 g/dL, leukocytes 46730/μL, and neutrophils 93.8%. The peripheral blood smear result was MPN: CNL. Bone marrow aspiration result matched CNL. BCR-ABL results were negative. Laboratory results 3 months later showed leukocytes 32640/μL and neutrophils 91.6%. CNL diagnosis criteria based on the 2017 World Health Organization include additional criteria if CSF3R mutation is absent: persistent neutrophilia (≥3 months), splenomegaly, and no reactive neutrophilia or plasma cell neoplasm. Proper diagnosis could prevent this disease from transforming into acute leukemia.