NEAR-TETRAPLOIDY IN ADULT ACUTE MYELOGENOUS LEUKEMIA

Tetraploidy and near-tetraploidy are observed infrequently in hematolo gic malignancies, most commonly seen in cases of childhood acute lymph oblastic leukemia, and are associated with large blast size. Four case s of adult acute myelogenous leukemia (AML) with tetraploid or near-te tra-ploid karyotypes are reported, along with review of the related li terature. AML subtypes included M0, M1, M4, and M5b. Tetraploidy was d etermined cytogenetically and confirmed by image cytometry (DNA index 2.0). The subjective impression of large blast size was confirmed by i mage cytometry, demonstrating mean blast nuclear areas of 237, 177, 20 3, and 216 mu(2), (mean 208 mu 2) in the cases with tetraploidy, compa red to a mean of 134 mu(2) in 10 control cases of AML with diploid or near-diploid chromosome patterns. The clinical course was variable in the four cases reported. When compared with previously published cases , the occurrence of tetraploidy or near-tetraploidy in adult AML, unli ke childhood ALL, does not appear to define a distinct subgroup in ter ms of FAB classification or to carry prognostic implications.