Double minute chromosomes in monoblastic (M5) and myeloblastic (M2) acute myeloid leukemia: two case reports and a review of literature.

Double minutes (dmin) are small, paired chromatin bodies that lack a centromere and represent a form of extrachromosomal gene amplification. Although they have been found in a variety of solid tumors, their presence in hematological malignancies, especially acute myeloid leukemia (AML), is rare. In addition, the presence of dmin may be a mechanism for upregulated oncogene expression and is generally associated with a poor prognosis. We describe two patients who had dmin at initial presentation of AML, including the first case of M5a with C-MYC amplification on dmin, and another case with C-MYC amplification as the only cytogenetic finding. We review here a total of 33 cases with dmin in AML. C-MYC was amplified by the dmin in 25 cases, while other putative oncogenes were amplified in the other 8.