A rare corticotroph-secreting tumor with coexisting prolactin and growth hormone staining cells

Abstract

Pituitary adenomas can express and secrete different hormones. Expression of pituitary hormones in nonneoplastic pituitary cells is regulated by different transcription factors. Some pituitary adenomas show plurihormonal expression. The most commonly reported plurihormonal adenomas are composed of somatotrophs, lactotrophs, thyrotrophs and gonadotrophs. Pituitary adenomas composed of both corticotroph and somatolactotroph secreting cells are not common because transcription factors regulating the expression of these hormones are different. We report a rare case of pituitary adenoma with concomitant corticotroph, prolactin, and growth hormone staining cells, review literature on similar cases, and discuss possible biological mechanisms underlying these plurihormonal tumors.

Figure 1

Pituitary MRI (post-contrast) showing microadenoma (thick arrow).

Figure 2

Pathology images of the tumor. (a) H&E stain of the larger tumor tissue showing abundant eosinophilic cytoplasm. (b) H&E stain of the smaller tissue showing abundant basophilic cytoplasm. (c) Immunohistochemistry: all of the cells in the larger adenoma were immunoreactive with antibodies to prolactin, and rare cells (Inset) were growth hormone positive. (d) Immunohistochemistry: cells of the small pieces of adenoma were ACTH positive.