INCIDENTAL ADENOMAS OF THE HUMAN PITUITARY-GLAND

Using conventional histological technique, we investigated 44 adenomas (31 men, 13 women) incidentally found in 36 pituitaries (25 men, 11 w omen) obtained from 1,117 unselected autopsies. The overall incidence of adenomas was 3.2% (men, 3.8%; women, 2.4%) without any significant sex predominance. Size, age distribution, and histological appearances of these adenomas were similar to those previously reported by others . Statistical analysis showed that the adenomas had a predilection for occurrence at the anterior margin of the gland. We further investigat ed 33 available adenomas with immunohistochemistry using antibodies fo r various adenohypophyseal hormones, S-100 protein, and glial fibrilla ry acidic protein, of which 6 contained growth hormone, 3 contained gr owth hormone and prolactin, 7 contained prolactin, 6 contained follicl e-stimulating hormone, 3 contained follicle-stimulating and luteinizin g hormones, 2 contained thyroid-stimulating and adrenocorticotrophic h ormones (separately), and 6 contained no adenohypophyseal hormones. No ne of adenomas revealed neoplastic proliferation of folliculostellate cells. To investigate tumor proliferation, nucleolar organizer regions were studied in 9 adenomas using the argyrophil method. The mean numb er per nucleus was slightly higher than that of corresponding, nontumo rous adenohypophysis at a statistically significant level. No adenoma caused symptoms of adenohypophyseal hormone abnormalities.