Chronic neutrophilic leukemia. Report of two cases and review of the literature.

Chronic neutrophilic leukemia is a rare, infrequently recognized, myeloproliferative disorder. It usually manifests as a leukemoid reaction, with mostly mature granulocytes in the peripheral blood, with rare to occasional immature forms, and sometimes with normoblasts. The clinical manifestations also include hepatosplenomegaly, elevated leukocytic alkaline phosphatase, elevated serum vitamin B12 and serum vitamin B12 binder ("R" fraction), and elevated serum uric acid. Distinction from a leukemegaly, the absence of sepsis, usually normal erythrocytic sedimentation, and the absence of fever. Leukemoid reactions may be associated with elevated serum vitamin B12 and uric acid, but the levels are usually lower than those found in chronic neutrophilic leukemia. Many patients have gouty symptoms, especially after treatment with Busulfan, and many have an unexplained hemorrhagic tendency, making major operations a risk. The authors add two cases to the 11 previously described.