Cytogenetic investigation of a low-grade endometrial stromal sarcoma (
ESS) revealed structural rearrangements of chromosomes 3, 6, and 7. Th
e karyotypic findings in the few cases of ESS reported reveal recurren
t involvement of both homologues of chromosome 7, with less consistent
changes affecting chromosomes 6 and 17. The cytogenetic and histologi
c features of these uterine stromal tumors require further study.