Transsphenoidal surgery for prolactin-secreting pituitary tumors: A study of 28 cases and review of the literature

Twenty-eight patients (22 women, six men) underwent transsphenoidal microsurgery for suspected prolactin-secreting pituitary tumors. Amenorrhea was present in 19 of the 22 women, and galactorrhea, in 21 of the 22 women and two of the six men. Prolactin values preoperatively ranged from 62 to 38,130 ng/ml, and the mean percentage decrease in serum prolactin (PRL) after surgery was 80% (range: 38% to 99%). Twenty patients had microadenomas (tumors <10 mm), and seven had macroadenomas (>10 mm). Although no tumor was found in one patient, her serum PRL fell from 65 to 24 ng/ml postoperatively. Surgical results depended upon both the initial PRL level and the tumor size. All eight patients with tumors of <10 mm and PRL levels of <200 ng/ml had normal postoperative prolactin values, whereas serum PRL returned to normal in only four of eleven patients with microadenomas but with preoperative PRL of >200 ng/ml. None of the five patients with macroadenomas in whom serum PRL had been measured preoperatively had normalization of serum PRL postoperatively, including one patient with a preoperative level of <200 ng/ml. Menses resumed in 11 of 18 women; galactorrhea improved in six of 11 subjects, and nine pregnancies have occurred. Analysis of these data, as well as those of 12 published series, suggests that both tumor size and the preoperative serum prolactin level are important factors in predicting the success of surgical therapy. Longitudinal follow-up is imperative to determine which patients are truly cured.