Squamous neoplasia in DES-exposed women.

The biological effect of DES (diethylstilbestrol) administered during the organogenetic period of pregnancy is teratogenic rather than carcinogenic. A series of 420 women exposed to DES during the 1st trimester of pregnancy were studied. Colposcopic examination revealed that the original squamocolumnar junction occurred in the vagina in 82% of the cases. During the process of squamous metaplasia there is danger that neoplastic transformation by carcinogens may occur in the vagina or cervix. Reports of the incidence of squamous intraepithelial neoplasia in DES-exposed women vary widely due to differences in patient selection numbers in the series and histologic interpretations. Diagnostic accuracy may be improved through the use of spectrophotometric evaluation of DNA content. The possibility that DES-exposed women have a higher risk of squamous neoplasia should be considered.