Chronic myelomonocytic leukemia with antecedent refractory anemia with excess blasts: further evidence for the arbitrary nature of current classification systems.

From a retrospective analysis of our series of myelodysplastic patients, we found 16 patients who were initially diagnosed as having a refractory anemia with excess of blasts (RAEB) according to FAB criteria, but later on (median time 4 months, range 2-8) developed a peripheral monocytosis >1 x 10(9)/L, leading to a disease re-classification into a dysplastic type of chronic myelomonocytic leukemia (MD-CMML). Analysis of clinical and prognostic aspects in this subgroup of patients as compared with those of primarily diagnosed MD-CMML patients, showed some significant differences in Hb level, platelet count, percentage of immature circulating precursor (IPC), bone marrow blastosis and trilineage dysplasia. Median survival for present group of patients was 33 months compared with 20 months for MD-CMML. Different prognostic scores were applied for evaluation of risk distribution and relative impact on survival prediction. We suggest on a possible atypical presentation of CMML and indicate a careful attention to be addressed to myelodysplastic patients who develop peripheral monocytosis, who might have a CMML variant, with more favourable prognosis and prolonged survival. Furthermore, we believe this is a further evidence for the arbitrary nature of current classification systems, which definitely exclude CMML from myelodysplastic syndromes.