Spontaneous ovarian choriocarcinoma, yolk sac carcinoma, and teratoma in B6C3F1 mice: a case report.

Three ovarian neoplasms (choriocarcinoma, yolk sac carcinoma, and teratoma) were diagnosed in a 2 yr carcinogenicity study involving B6C3F1 mice. The yolk sac carcinoma and the teratoma occurred in opposite ovaries of a single female mouse that was sacrificed in extremis on study day 725. The choriocarcinoma occurred in a female mouse that was sacrificed in extremis on study day 565. These neoplasms were considered to be spontaneous in origin.