Endocrine outcome after transsphenoidal adenomectomy for prolactinoma: prolactin levels and tumor size as predicting factors.

The level of prolactin in the serum was determined pre- and postoperatively in 90 patients who were operated upon transsphenoidally for prolactin-secreting pituitary adenomas. Twenty-three had microadenomas and 67 had macroadenomas. Those patients who were cured had a distinctly lower mean prolactin level (about 200 ng/ml or less) than those who were not cured. Of those patients whose adenomas were larger than 10 mm in diameter, only 39% were cured. The relationship between prolactin levels and tumor size and the return of menses and cure is discussed.