Cytogenetic findings in four malignant mixed mesodermal tumors of the ovary.

Short-term cultures of four malignant mixed mesodermal tumors of the ovary were cytogenetically analyzed. The primary tumor was examined in three cases, whereas in one case the sample was obtained from a residual tumor mass after chemotherapy. The tumor sampled after cytostatic treatment had a relatively simple karyotype with numerical changes that included pentasomy 12 and an i(1)(q10) as the only structural abnormality. Karyotypic analysis of the three primary tumors revealed extensive structural as well as numerical aberrations, i.e., a picture similar to that seen in the few malignant mixed mesodermal tumors with karyotypic anomalies described previously. Rearrangements of chromosome 1, leading to loss of distal 1p, and homogeneously staining regions have so far been the most frequent cytogenetic changes in this tumor type. Malignant mixed mesodermal tumors of the ovary thus seem to be karyotypically identical to the more numerous mixed mesodermal tumors of uterine origin, and they do not differ substantially in this respect from pure ovarian carcinomas.