Chronic myelomonocytic leukemia in childhood: a retrospective analysis of 110 cases. European Working Group on Myelodysplastic Syndromes in Childhood (EWOG-MDS).

Chronic myelomonocytic leukemia (CMML) is a rare hematopoietic malignancy of childhood. To define the clinical and hematologic characteristics of the disease, we performed a retrospective analysis of 110 children given the diagnosis CMML irrespective of karyotype. Median age at diagnosis was 1.8 years. Neurofibromatosis type 1 was known in 14% and other clinical abnormalities in 7% of the children. At presentation, the medium white blood count was 35 x 10(9)/L, with a median monocyte count of 7 x 10(9)/L. Karyotypic abnormalities in bone marrow cells were noted in 36% of the patients, whereas 26% of the children had monosomy 7. Children with monosomy 7 did not differ from those with normal karyotype with respect to their clinical presentation. However, they did display some characteristic hematologic features. Of 110 children, 38 received an allogeneic bone marrow transplant (BMT). The probability of survival at 10 years was 0.39 (standard error [SE] = 0.10) for the BMT group and 0.06 (SE = 0.4) for the 72 patients of the non-BMT group. Platelet count, age, and hemoglobin F at diagnosis were the main predicting factors for the length of survival in the non-BMT group. There is a strong need for a broad agreement on nomenclature in children with myelodysplastic syndromes (MDS). We propose here to use the French-American-British classification for MDS in childhood.