Atypical vaginal adenosis and cervical ectropion. Association with clear cell adenocarcinoma in diethylstilbestrol-exposed offspring.

Knowledge of the evolution of clear cell adenocarcinomas of the vagina and cervix in diethylstilbestrol-exposed progeny has remained elusive despite the known topographical association of these tumors with the tuboendometrial form of vaginal adenosis and cervical ectropion. Twenty radical hysterectomy or radical hysterectomy and vaginectomy specimens of clear cell adenocarcinoma of the vagina or cervix were serially blocked in toto; tuboendometrial epithelium was found in the vagina in 19 (95%) of the cases, usually in greatest concentration at the margin of the tumor, particularly inferiorly. Foci of atypical tuboendometrial epithelium were identified in 16 (80%) of the cases, almost always immediately adjacent to the tumor. Twenty-five of a second group of 47 specimens in which only substantial portions of the vagina or cervix adjacent to a clear cell adenocarcinoma were available for examination also had foci of atypical tuboendometrial epithelium. The frequency with which atypical tuboendometrial glands in the vagina and cervix were associated with the carcinomas and the proximity of the former to the latter provide strong evidence that atypical vaginal adenosis and atypical cervical ectropion of the tuboendometrial type are precursors of clear cell adenocarcinoma.