Chronic neutrophilic leukemia (CNL): a clinical, pathologic and cytogenetic study

This report describes a single institution's recent experience with six pat ients fulfilling the diagnostic criteria of chronic neutrophilic leukemia. No patient had the Philadelphia chromosome or the BCR/ABL fusion gene. None of the common cytogenetic abnormalities characteristic of myeloid disorder s were detected. Two patients demonstrated clonal evolution during the cour se of the disease. All responded initially to therapy with hydroxyurea with control of leukocytosis and reduction in splenomegaly. Three patients even tually became refractory to hydroxyurea, manifesting progressive neutrophil ia without blastic transformation. Aggressive chemotherapy to control progr essive leukocytosis resulted in death due to cytopenias in two of these pat ients. The third patient received less intensive chemotherapy and died of p rogressive disease. One patient died after transformation of the disease in to undifferentiated acute myeloid leukemia. Two patients remain alive with stable disease on hydroxyurea therapy, 12 and 54 months after initial diagn osis. Chronic neutrophilic leukemia is a rare clinicopathologic entity that can be distinguished from chronic myelogenous leukemia, the recently descr ibed neutrophilic-chronic myelogenous leukemia, and myelodysplastic syndrom e. The clinical course is heterogeneous, with a definite risk of death from either blastic transformation or progressive neutrophilic leukocytosis. Co ntinued study and reporting of these cases must be encouraged.