[An experimental induction of teratomatous tumor in rats].

Extrauterine implantation of the fetal membrane was performed in Wistar King A strain rats by the technique of fetectomy at the time of the twentieth gestational day. Thirty-five rats received fetectomy alone, and in nineteen rats the fetectomy was combined with 7,12-dimethylbenz (a) anthracene (DMBA) application. The results obtained were as follows: In the fetectomy group, 23(65.7%) tumors 17(73.9%) mature teratomas and 6(26.1%) yolk sac tumors occurred. In the group which also received the application of DMBA, the tumors were found in seven of 19 rats (36.8%). The incidence of yolk sac tumor was 28.6% in this group and the remaining five tumors were mature teratomas. The direct application of the carcinogen did not affect the incidence or histology of the induced tumor. To identify the exact histogenesis of these teratomatous tumors from the fetal membrane, further research is necessary.