Massive hyperdiploidy and tetraploidy in acute myelocytic leukemia and myelodysplastic syndrome.

Massive hyperdiploidy (>50 chromosomes) and tetraploidy (4n) are rare cytogenetic abnormalities in myelocytic malignancies, and their significance is unknown. We report on 11 patients with acute myelocytic leukemia (AML) and two patients with a myelodysplastic syndrome (MDS) with massive hyperdiploidy (10 patients) or tetraploidy (3 patients) seen at our institution over a 12-year period. Eleven patients were male and two were female. Age range was 44-84 years (median, 70 years). Only one AML patient had a previous MDS, and no patient had therapy-related disease. One or more copies of chromosomes 8 and 19 were gained in eight patients each; other frequently gained chromosomes included 13, 15, and 21. Eight patients had structural abnormalities in addition to chromosome gain; del(5q) was most common (five patients). Eleven patients received induction chemotherapy, but only four achieved complete remission. Survival ranged from 1 to 22 months, with a median of 6 months. We conclude that massive hyperdiploidy and tetraploidy are infrequent abnormalities in AML and MDS, are seen primarily in de novo disease in older male patients and are associated with a low remission rate and short survival. Massive hyperdiploidy and tetraploidy define a prognostically unfavorable cytogenetic group in de novo AML.