Argyrophil granules in the human pituitary.

In order to assess the value of the Grimelius silver method in adenohypophysial cell identification and adenoma diagnosis, 22 nontumorous adenohypophyses and 50 pituitary adenomas were investigated. Grimelius positivity was localized, as documented by mirror sections, predominantly in PAS and led hematoxylin positive cells; but a few negative cells contained argyrophil granules as well. The immunoperoxidase method revealed Grimelius positivity primarily in corticotrophs, thyrotrophs and gonadotrophs, and occasionally in somatotrophs and lactotrophs. Argyrophilia was readily demonstrated in 11 out of 13 corticotroph cell adenomas, in 1 out of 1 thyrotroph cell adenoma, in 5 of 11 null cell adenomas and in 4 out of 5 oncocytomas. No argyrophilia was detected in 5 growth hormone cell adenomas and 5 prolactin cell adenomas. One our of 5 mixed, growth hormone cell-prolactin cell adenomas, and 1 out of 5 acidophil stem cell adenomas showed Grimelius positivity. By electron microscopy, silver grains were localized in the secretory granules. It can be concluded that no specific hormonal products account for argyrophilia.