pubmed-article:523019 | pubmed:abstractText | For the development of the DES carcinoma syndrome, two different mechanisms may be assumed. 1. Indirect effect via teratogenesis: squamous cell carcinoma develops from adenosis vaginae with the assistance of cofactors (Fig. 6). Till now, a conversion of adenosis to clear cell carcinoma has never been observed (Hilgers, 1977). Adenosis is probably a precancerous lesion only for squamous cell carcinoma. 2. Transplacental terato-oncogenesis: clear cell carcinoma as a mesonephric carcinoma develops from persisting wolffian ducts with a latent period of 15 to 20 years. DES here acts only as a promoter by way of the transplacental teratogenic mechanism, thus as a terato-co-carcinogenic factor (Fig. 6). | lld:pubmed |