The long-term follow-up of the transsphenoidal microsurgical treatment in 119 consecutively operated women with a PRL-secreting adenoma is presented. An apparent total removal of the tumor was achieved in 98 cases with an enclosed tumor (58 grade 1 and 40 grade II). In the remaining cases the removal was considered partial. The achievement of persistent normal PRL basal levels was verified in 61 patients (44 grade I and 17 grade II) who had an apparent total removal of the adenoma. In the 37 remaining patients who were thought at surgery to have had total removal we have distinguished two groups: 30 patients showed a "relapse" or "persistence" of PRL levels below 200 ng/ml without clinical and radiological signs of tumor regrowth, and 7 patients with a PRL level higher than 200 ng/ml who had evidence of PRL-secreting tumor recurrence.