Prolactin-secreting pituitary adenoma: occurrence following prenatal exposure to diethylstilbestrol.

A case is reported of a prolactin-secreting pituitary adenoma in a young woman who had been referred for evaluation of amenorrhea with a history of in utero exposure to diethylstilbestrol. Following prolactin suppression ans stimulation tests bromocriptine (Parlodel), 2.5 mg orally, twice a day was prescribed. Followup at 1, 2, and 3 years after diagnosis with the use of sector scans of the sella turcica showed a decrease in size of the tumor from 12 x 12 mm in 1980 to 9 x 6 in 1982, over 50% reduction. Serum prolactin level measured 3 months after initiation of treatment was reduced by about 2/3 to 124 ng/ml. The direct role of estrogen in pituitary tumorigenesis in animals has been suggested both by the demonstration of estrogen receptors in the cytosol of estrogen-induced prolactinomas and growth inhibition of a transplantable estrogen-induced prolactin-secreting pituitary tumor by the administration of tamoxifen. In this case bromocriptine, a dopaminergic agonist, was successful in reducing both serum prolactin levels and tumor size.