Incidental pituitary adenomas: a retrospective study.

A retrospective study was performed to study the incidence, morphology, and endocrine activity of incidental pituitary tumors in 500 consecutive autopsied subjects. Forty-two pituitary glands were found to have occult pituitary adenomas. These tumors were more frequently found in patients who died in the sixth or seventh decade of life. There was no obvious sex predominance. Of these patients 48% were obese, 34% were diabetic, and 57% were hypertensive. However, in only one case a pituitary lesion was clinically questioned but specific endocrine functions were not performed. The tumor size ranged from 1 to 15 mm, with 62% of tumors being less than 3 mm. In 34 cases the tumors were located along the lateral aspect of the gland, and 36% of these tumors stained positive for the presence of prolactin. Suspicious or abnormal areas were found in 11 of 17 cases in which skull x-rays were taken. In this article we discuss the factors that may affect the recovery incidence of occult pituitary adenomas. The biologic behavior of these microadenomas, especially those classified as prolactinomas, is unclear, but there clinical effects appears to be relatively benign.