A retrospective review of 120 patients undergoing transsphenoidal surgery for pituitary adenomas revealed that computed tomography (CT) was less sensitive and less specific than hormonal methods in identifying residual functioning adenomas. However, CT was the only useful method of evaluating nonfunctioning tumors, including pseudo-prolactinomas. Enlargement of the pituitary stalk, when seen on preoperative CT, was 100% predictive of "cure" if the enlargement returned to normal size on a remote follow-up scan (n = 8) and was 100% predictive of residual tumor if the enlargement persisted or evolved (n = 8). Resolution of stalk displacement was the next most reliable predictor of cure (91%, n = 11), but persistent displacement was less reliable than abnormal intrasellar enhancement in predicting the presence of residual tumor (71%, n = 28, vs. 81%, n = 26). Enhancement in the postoperative sella by other than normal pituitary gland was presumed to be due to inflammation in 19% of patients. Inflammatory enhancement was observed in the presence of autograft and homograft muscle plugs and, unlike enhancement due to untreated tumors, was observed to decrease in size and intensity with time. Intrasellar enhancement was an unreliable criterion of success or failure in cases of microadenoma. All 14 patients with functioning adenomas and preoperative parasellar tumor extension had persistent tumor at postoperative evaluation. Of the 47 patients with resected functioning adenomas who had CT scans showing empty or partly empty sellas after operation, 22 (47%) had hormonally detectable residual tumor.