Diversity of Bone Marrow Findings in Chronic Myelomonocytic Leukemia

Abstract

Since the early 1970s, when chronic myelomonocytic leukemia (CMML) was described as a novel type of leukemia, this entity has drawn our particular interest. At the beginning the disorder was separated from chronic myelogenous leukemia and, for about 10 years, was indisputably classified with myeloproliferative diseases. In 1982 a French-American-British (FAB) cooperative group decided to include CMML in the larger group of myelo-dysplastic syndromes (MDS) and to define diagnostic criteria. According to the authors’ conceptions, the disease is now included either among myeloproliferative syndromes, particularly Philadelphia chromosome- (Ph¹)-negative chronic myelocytic leukemia (CML), or among MDS. To our mind, the reason for such different approaches lies in the extreme biological and clinical diversity of features observed in these patients. As to blood, some opposite (diminished or increased) values in all three cell lines may occur. When examining the bone marrow smears, a significant diversity is usually observed both in the extent of myeloid hyperplasia and, especially, dysplasia. Finally, CMML as defined by the FAB group is associated with a variable survival rate, ranging from a few weeks to several years. Taking into account all the above data, we tried to find a reasonable explanation of these divers observations and, moreover, to identify subgroups within our patients.