[Karyotype in chronic myeloid leukemia in a blastic crisis. II. Trisomy 17]

One case of a patient with Chronic Granulocytic Leukemia showing a double Ph' together with trisomy 17 during blastic crisis is reported. The Ph' chromosome resulting from a standard translocation of the chromosomes 9 and 22 was present in all the 16 mitoses observed, while the trisomy 17 was found in 15. This case is an additional contribution which demonstrates the presence of the alterations of the chromosome group E during the blastic crisis.