Trisomy 4 and double minutes in acute myeloid leukemia: further evidence that double minutes can occur as the primary cytogenetic abnormality.

The specific association of trisomy 4 and double minutes (dmin) is rare and is usually reported in patients with acute myeloid leukemia (AML), primarily M2 and M4 subtypes. Several previous reports describing this combination suggested that trisomy 4 was the primary cytogenetic abnormality, and that the presence of the dmin was secondary. We describe a 79-year-old male who presented with myelodysplasia, transforming to AML-M2. Cytogenetic analysis of bone marrow aspirate cultures showed a 46,XY,dmin[12]/47,XY,+4,dmin[7]/46, XY[6] karyotype. The number of dmin ranged from 1 to 150. Fluorescence in situ hybridization (FISH) analysis showed that the dmin were derived from amplification of the MYC oncogene. Dual-color interphase FISH analysis was performed with D4Z1 and MYC probes and showed no evidence of a clone containing trisomy 4 without dmin. These data suggest that dmin may also occur as the primary cytogenetic abnormality in patients with trisomy 4 and dmin.