Abstract

Chronic neutrophilic leukemia is a very rare myeloproliferative disorder. It is characterized by severe sustained neutrophilic leukocytosis, hepatosplenomegaly, elevated leukocyte alkaline phosphatase score, elevated serum vitamin B12,, negative Philadelphia chromosome and the absence of fever or an underlying infection or disease capable of provoking a leukemoid reaction. We have experienced a typical case of chronic neutrophilic leukemia in 75 years old man who complained a huge intramuscular hematoma due to bleeding tendency despite normal finding of coagulation test. Philadelphia chromosome was negative with normal karyotype and he showed marked neutrophilic leukocytosis with 92.2% segmented neutrophil, elevated leukocyte alkaline phosphatase score, and reduced GM-CFU(granulocyte macrophage-colony forming unit).

• Keywords: Chronic neutrophilic leukemia, Philadelphia chromosome negative, GM-CFU