Clear-cell adenocarcinoma of the vagina

Clear-cell adenocarcinoma (CCA) of the vagina (or cervix) is a rare cancer often linked to the drug diethylstilbestrol (DES), which was prescribed in the mistaken belief that it prevented miscarriage and ensured a healthy pregnancy.

History
This synthetic estrogen was given to millions of pregnant women in the United States, primarily from 1938-1971 but not limited to those years. Internationally, DES use continued until the early 1980s. DES was given if a woman had a previous miscarriage, diabetes, or a problem-pregnancy with bleeding, threatened miscarriage or premature labor. Up until the mid to late 1950s some women were given DES shots. After that, DES was primarily prescribed in pill form. DES also was included in some prenatal vitamins. In the late 1960s through 1971 a cluster of young women, from their teens into their twenties, was mysteriously diagnosed with CCA, a cancer not generally found in women until after menopause. Doctors at Massachusetts General Hospital in Boston eventually linked DES exposure before birth to the development of CCA in these young woman. They determined the risk for developing CCA among so-called DES Daughters is small, estimated at 1 in a 1,000.

Clinical features
After age 30 it was thought DES Daughters no longer were at risk for the disease, but as they age into their 40s and 50, cases continue to be reported. Researchers are now watching for a possible spike of CCA cases in post-menopausal DES Daughters, since this is when this cancer is normally diagnosed.

According to the Centers for Disease Control and Prevention (CDC), DES Daughters should have a special pap/pelvic exam every year because of their lifelong risk for clear-cell adenocarcinoma. The screening is similar to a routine exam but is more comprehensive and should be done every year for DES Daughters even after a hysterectomy. Although the cervix was removed in surgery, the vagina remains, and should be examined for the possible development of CCA. Updated screening guidelines in 2012 allow some women to skip annual Paps. But in developing the guidelines, the United States Preventative Services Task Force (USPSTF) specifically spelled out that the guidelines do NOT apply to DES Daughters, who should continue having annual screenings.

Clear cells are rich in glycogen, which accounts for their histology.