A case of atypical chronic myeloid leukemia regarded as MDS with myeloproliferative features

We report a case of atypical chronic myeloid leukemia (aCML) who showed mar ked neutrophilia without dysplastic features, basophilia or monocytosis. Th ese findings diverged somewhat from the FAB criteria for aCML. The patient' s erythroid cells and megakaryocytes were dysplastic. His marrow cells form ed no spontaneous colonies, as shown by cell culture. The cells formed many small-sized neutrophil colonies with G-CSF stimulation. Interestingly, the y formed mainly neutrophil colonies with GM-CSF stimulation. These findings were different from those of chronic myelomonocytic leukemia cells and chr onic granulocytic leukemia cells. This aCML case showed the cytological fea tures of myelodysplastic syndrome.