Structural chromosomal abnormalities are common in myelodysplastic syn
dromes (MDSs), and complex abnormalities are known to confer a poor pr
ognosis. Polyploidy is rare. We report a patient with MDS in whom 8/15
cells were 77,XYY; 2/15 were 83,XYY, and 5/15 were diploid (46,XY). H
e experienced rapid evolution of disease, transforming to terminal acu
te leukemia. (C) Elsevier Science Inc., 1998.