Objective: To report two cases of leukemia with t(8;21) and tetraploid clones.
Methods: R-banding technique was used.
Results: Cytogenetic studies of BM cells at diagnosis revealed that each of the two cases had three related abnormal clones besides a normal one: 46, XY, t(8;21) (2%), 46, idem, add((7)(q31)(6.8%) and 92, idem x 2 (80.6%) in case 1 and 46, XX, t(8;21) (13.4%), 47, idem, + 4 (46.3%) and 94, idem x 2 (39.1%) in case 2. They did not obtain complete remission on chemotherapy and survived 4 and 6 months, respectively.
Conclusion: Tetraploid or near tetraploid clones are secondary events which are specifically associated with t(8;21) leukemia and the prognosis of patients with this kind of abnormal karyotype is poor.