[AFTER YEARS OF WANDERING, CHRONIC MYELOMONOCYTIC LEUKEMIA FINALLY FOUND ITS PLACE: A HISTORICAL PERSPECTIVE].

Proliferation of monocytes (MO) occurs in reactive conditions as well as in myeloid neoplasm with clonal monocytosis such as chronic myelomonocytic leukemia (CMML). CMML is a type of clonal hematopoietic disease characterized by a sine qua non condition: sustained peripheral blood monocytosis (absolute monocytes count from ≥1 X109/L, to ≥0.5 X109/L with monocytes accounting for ≥10% of the peripheral white blood cells), accompanied by overlapping changes in bone marrow of myelodysplasia and myeloproliferation, <20% blasts and presence pf clonality. In CMML, there is an inherent risk for leukemic transformation (15% over 3-5 years). The French-American-British (FAB) co-operative group, created in 1976, proposed a uniform system of classification and nomenclature of hemato-oncologic malignancies. Classification of hematopoietic neoplasms is essential for making proper evidence-based treatment decisions and accurately assessing prognosis.