Double-minute chromosomes appearing in a patient with myelodysplastic syndrome with disease evolution.

We present the first case of a myelodysplastic syndrome (MDS) demonstrating an association between the appearance of double-minute chromosomes (dmin) and disease progression. This 59-year-old Japanese woman showed a deletion of the long arm of chromosome 5 [del(5)(q21q34)] and monosomy 9, when she was diagnosed as having refractory anemia with an excess of blasts (RAEB). Subsequential cytogenetic analyses demonstrated that the neoplastic cells in the peripheral blood had six copies of dmin, when the disease progressed into RAEB in transformation (RAEBt). This cytogenetic change was consistently observed when the patient developed the leukemia phase. The findings in this case suggest that the appearance of dmin may be linked to progression of the disease.