Ovarian mature cystic teratoma with malignant transformation. An interphase cytogenetic study.

The chromosomal composition of cancers arising in ovarian mature cystic teratoma (MCT) was analyzed using chromosome in situ hybridization (CISH) performed on paraffin-embedded material from 10 squamous cell carcinomas, 1 adenocarcinoma, 1 thyroid papillary carcinoma, and 1 strumal carcinoid. Cervical tissue from seven of these patients was used as a control. In the cancers, a relative gain of chromosome 16 (in 7 cases), chromosome 12 (in 9), chromosome 11 (in 10), and chromosome X (in 8) was detected. Trisomy 12 was diagnosed in eight cases. No chromosomal aberrations were detected in the strumal carcinoid. In the benign areas of the MCTs, only one case showed a gain of chromosome 11, although, in another case, there was a gain of chromosome X. Malignant transformation of MCTs often occurs in association with complex chromosome aberrations that may play a role in the development of such carcinomas.