Cytogenetic evidence of clonal evolution in a case of hemopoietic dysplasia with a 5q- chromosome.

A 70-year-old Japanese male with hemopoietic dysplasia is described. Cytogenetic investigation revealed an abnormal karyotype, 46,XY,del(5)(q13q33), in all metaphases examined at the time of diagnosis. Eight months later, a newly appearing abnormal hyperdiploid karyotype, 47,XY,5q-, +21, was observed in 74% of the cells analyzed, which was associated with evolution of the disease when a pathologic diagnosis of a myeloproliferative disorder was made.