Blast cells with nuclear extrusions in the form of micronuclei are associated with MYC amplification in acute myeloid leukemia.

We report three cases of acute myeloid leukemia without maturation [AML-M1 subtype according to the French-American-British classification (FAB)] with the presence of MYC oncogene amplification in form of double minutes (dmin) or homogeneously staining region (hsr). Blasts cells showed a particular morphology with extrusion of chromatin material. We observed by FISH the phenomenon of MYC aggregation in interphase cells and the formation of micronuclei excluded from the nucleus. The appearance of chromatin extrusion in cytological analysis should draw attention of the presence of dmin aggregation and possible MYC amplification.