CHRONIC NEUTROPHILIC LEUKEMIA - A STUDY OF 4 CASES

Chronic neutrophilic leukemia (CNL) is a very rare entity, which has t o be included among the chronic myeloid leukemias. Once an underlying cause of neutrophilia is excluded, the diagnosis of CNL is based on ex clusion of chronic granulocytic and other types of chronic myeloid leu kemias. The classification proposed by Sheperd et al. has proven to be helpful, but it must be completed by cytogenetic analysis and the sea rch for bcr rearrangement by molecular biology methods, in order to co nfirm the absence of Philadelphia chromosome and of bcr-abl hybrid gen e. We report here four cases of CNL, with confirmed absence of bcr rea rrangement in two cases. Two patients died, 12 and 8 years after diagn osis, the second one following transformation into myelofibrosis with myeloid metaplasia. The other two died of acute myelogenous leukemia, the first one, 25 years after diagnosis of CNL, following a 3-year pha se of acceleration. The last patient presented combined features of CN L and refractory anemia with excess of blasts, and was characterized b y both progressive leukocytosis and severe thrombocytopenia; acute tra nsformation into acute myelogenous leukemia occurred 6 months after di agnosis and death 1 month later. Among the 30 cases reported so far, p lus the four presented here, combined myelodysplastic features were ob served in five cases and transformation into acute myelogenous leukemi a in six. Chronic neutrophilic leukemias should be reported regularity , in view of the uncertain and low frequency of this hematological dis ease.