Ovarian nongestational choriocarcinoma and associated adenocarcinoma with the same germ cell origin determined by a molecular genetic approach: A case report.

Ovarian non-gestational choriocarcinomas co-existing with adenocarcinoma are extremely rare and have been reported as epithelial ovarian carcinomas of a "non-germ cell origin" with "choriocarcinomatous differentiation". Although the cellular origin of non-gestational choriocarcinoma may be post-meiotic ovarian germ cells or the dedifferentiation of epithelial ovarian carcinoma, detailed genetic evidence has not yet been obtained to support this. We herein present a case of ovarian non-gestational choriocarcinoma co-existing with adenocarcinoma in a 29-year-old woman. The tumor rapidly increased in size and lung metastases appeared soon after parturition. We genetically demonstrated that the cellular origin of ovarian non-gestational choriocarcinoma was a post-meiotic germ cell derivation using a short tandem repeat analysis. The co-existing adenocarcinoma component was also shown to be of the same germ cell origin. These tumors showed the same homozygous pattern. A molecular genetic approach may be important for understanding the clinicopathological features of such tumors.