Subclinical adenomas of the human pituitary. New light on old problems.

We studied 107 adenomas, found incidentally at autopsy in 100 pituitaries, by histologic and immunohistochemical techniques to elucidate their cellular composition and hormone content. No adenohypophyseal hormones were found in 54 (50%) of the adenomas, whereas prolactin was shown in 45 (42%). Of the remaining tumors, two contained prolactin and growth hormone, four contained adrenocorticotropic hormone, one contained thyroid-stimulating hormone, and one contained luteinizing hormone. These findings are consistent with the view that all adenohypophyseal cell types can give rise to neoplasms. No correlation was found between clinical history, autopsy findings, or cause of death and the presence or type of adenoma. The adenomas caused neither local symptoms nor endocrine abnormalities. The prevalence of various adenoma types differed between autopsy specimens and surgical material.