Diethylstilbestrol-exposed monozygotic twins discordant for cervicovaginal clear cell adenocarcinoma.
This case report describes a discordant response to in utero exposure to diethylstilbestrol (DES) in a set of assumed monozygotic twins, one of whom contracted clear cell adenocarcinoma of the vagina and one of whom did not. The monozygotic twins were examined at age 17. In both women, there were benign teratologic changes. This discordance suggested that other factors besides in utero exposure to DES may account for the development of cervicovaginal clear cell adenocarcinoma; these factors would necessarily be extrauterine in location and nongenetic in character. When the twins were compared for lifetime exposure to radiation and evidence of previous viral disease in an attempt to determine the other possible etiological considerations, the twin with cancer showed an elevated titer of antibody to the capsid antigen of Epstein-Barr virus, a virus of the herpesvirus group which has been implicated in oncogenicity. The cancerous twin was treated with surgery and radiation, and the tumor has not reappeared; 4 years later the nonaffected twin remains unaffected also.