[Clinical study on heterogeneity of chronic myelomonocytic leukemia]

We examined fourteen patients with chronic myelomonocytic leukemia (CMMoL) according to the following staging criteria at diagnosis; Group A: bone marrow (BM) blast less than 5% (eight cases), Group B; BM blast more than 5% and less than 30% (five cases), Group C; BM blast more than 30% (one case). Compared with Group A, Group B patients have much more peripheral blood leukocyte, granulocyte and monocyte counts, LDH level, and serum and urine lysozyme levels. Two of the five Group B cases transformed to acute leukemia (BC) within one and a half year, and other three patients died of infection and hemorrhage within a year. On the contrary, three of the eight Group A patients survived four years, and transformation to acute leukemia occurred in only one case after four years. Autopsy revealed multiple organ infiltration of monocytoid granulocytes on the patients with advanced stage and more bone marrow blasts. Two cases have coexistence of myeloproliferative disorders, one with essential thrombocythemia, and another with myelofibrosis, which, later, transformed to acute leukemia. And a Group C patient transformed to chronic phase with chemotherapy, and maintained the state for six years, but at the end stage, mature monocytes increased and pancytopenia developed. These findings indicate the heterogeneity of CMMoL in respect of the disease stage and the coexistence of other myeloproliferative disorders.