Chronic neutrophilic leukemia
Chronic neutrophilic leukemia differs in the blood picture from chronic myeloid leukemia by its lower leukocytosis and the absence of immature forms of myelopoiesis in the blood or by the presence of very small numbers of them. These signs are not enough for the differential diagnosis of these diseases, so the diagnosis of neutrophilic leukemia is made only on the basis of cytogenetic data. Previously, Ph (BCR-ABL) -negative cases and BCR-ABL-positive chronic myeloid leukemia with p230 protein production were ranked as chronic neutrophilic leukemia. In this classification, the diagnosis of chronic neutrophilic leukemia is left only for the BCR-ABL-non-affective variant; a disease with t (9; 22) and p230 protein production is considered as a variant of chronic myeloid leukemia. This seems to us to be absolutely fair and corresponding to the role of t (9; 22) in the pathogenesis of the disease.
In determining chronic eosinophilic leukemia and the hypereosinophilic syndrome, difficulties in differential diagnosis are emphasized. Currently, the hypereosinophilic syndrome includes a heterogeneous group of diseases characterized by persistent high eosinophilia of unknown origin. Appeared work, which showed that, at least in some cases, high eosinophilia occurs as a result of interstitial deletion of the long arm of chromosome 4 and the consequent formation of a chimeric gene with tyrosine kinase function. It is possible that such cases will be referred to as eosinophilic leukemia and the name “hypereosinophilic syndrome” will disappear, but now this term is used in all publications.
It should be recognized that this introduces a certain confusion, since reactive eosinophilia is sometimes described in practice under this term. At the same time, hypereosinophilic syndrome is a clearly defined symptom complex with a severe course and almost always an extremely poor prognosis. Cytogenetic analysis in cases of hypereosinophilia of unclear genesis is very important, since with eosinophilic syndrome with interstitial deletion of chromosome 4, Gleevec is effectively used.