title: A case of macroprolactinoma with subclinical growth hormone production.
abstract: We describe a rare case of macroprolactinoma with subclinically synchronous growth hormone (GH) production. A 59-year-old man with a giant adenoma in his pituitary had elevated serum prolactin (PRL) and insulin-like growth factor (IGF)-I levels, despite normal levels of basal GH. Serum GH levels were paradoxically increased in response to an intravenous administration of thyrotropin-releasing hormone (TRH). Prolonged exposure to glucose as a result of oral glucose tolerance testing (oGTT) failed to decrease GH levels. Two-week treatment with cabergoline, a dopamine D2 receptor agonist, decreased serum PRL and GH levels, and size of the tumor. Immunohistochemistry and in situ hybridization revealed PRL-producing cells capable of synchronous GH production. Acidophilic stem cell adenoma may be responsible for these phenomena. The nature of high proliferation and invasive tumor growth should be kept in mind when managing patients with this cell type of adenoma. IGF-I levels should be followed in PRLoma, even when basal GH levels are within the normal range, because mixed PRL- and GH-producing tumors would lie underneath. Further endocrinological examinations such as TRH test and oGTT are recommended when elevated IGF-I levels are detected.
authors: Third Department of Internal Medicine, Hirosaki University School of Medicine, Aomori, Japan.
authors: Kazunori
authors: K
authors: Kageyama
authors: Takeshi
authors: T
authors: Nigawara
authors: Yoshimasa
authors: Y
authors: Kamata
authors: Toshio
authors: T
authors: Takahashi
authors: Jiichi
authors: J
authors: Anzai
authors: Shigeharu
authors: S
authors: Suzuki
authors: Yoshiyuki R
authors: YR
authors: Osamura
authors: Toshihiro
authors: T
authors: Suda
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000096:biosynthesis; D003907:Dexamethasone / Q000008:administration & dosage; D005938:Glucocorticoids / Q000008:administration & dosage; D019382:Human Growth Hormone / Q000096:biosynthesis* / Q000097:blood / Q000235:genetics; D006801:Humans; D006854:Hydrocortisone / Q000096:biosynthesis; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007334:Insulin-Like Growth Factor I / Q000032:analysis / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D011388:Prolactin / Q000097:blood / Q000235:genetics / Q000378:metabolism; D015175:Prolactinoma / Q000378:metabolism* / Q000473:pathology
chemical_list: D005938:Glucocorticoids; D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I; D003907:Dexamethasone; D000324:Adrenocorticotropic Hormone; D011388:Prolactin; D006854:Hydrocortisone