title: "Silent" thyrotropin (TSH) expression in acromegaly and clinically non-functioning pituitary adenomas.
abstract: BACKGROUND
  The pituitary adenomas secreting thyrotropin (TSH) are considered the rarest type of hormonally active pituitary tumour. In spite of that, many cases are described in the literature. On the other hand, the observations of the co-expression of TSH with other pituitary hormones (mostly with growth hormone [GH]) and "silent" expression of TSH in clinically non-functioning pituitary adenomas (CNFPA) are rather scarce.
  
  
  METHODS
  Among 93 examined pituitary adenomas, 22 of them were diagnosed as active acromegaly and 71 as clinically non-functioning pituitary adenomas (CNFPA). All of them were immunostained with antibodies against pituitary hormones, including the anti-TSH antibody. TSH-immunopositive adenomas are immunostained also to detect somatostatin receptor subtypes (SSTR 1-5).
  
  
  RESULTS
  TSH immunopositivity was found in 4.2% of CNFPA (3/71 tumours) and in 13.6% (3/22) cases of somatotropinomas manifesting as active acromegaly. All of the examined TSH-immunopositive adenomas expressed SSTR subtypes except SSTR4. The symptoms of hyperthyroidism were not observed in any of the acromegalic patients co-expressing TSH with GH.
  
  
  CONCLUSIONS
  Our data confirm the relative rarity of TSH expression or co-expression of TSH in pituitary tumours. In most cases TSH is co-expressed with GH in patients with acromegaly and is not accompanied by hyperthyroidism. The "silent" expression of TSH may occur also, although rarely in CNFPA. The strong expression of SSTR in TSH-immunopositive CNFPA ("silent thyrotropinoma") indicates the possibility of the treatment of these tumours with somatostatin analogues. (Endokrynol Pol 2016; 67 (5): 515-518).
authors.affiliation: Department of Immunoendocrinology. Chair of Endocrinology, Medical University of Lodz. pawlikowski.m@wp.pl.
authors.forename: Marek
authors.initials: M
authors.lastname: Pawlikowski
authors.forename: Hanna
authors.initials: H
authors.lastname: Pisarek
authors.forename: Maria
authors.initials: M
authors.lastname: Jaranowska
authors.forename: Maciej
authors.initials: M
authors.lastname: Radek
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Winczyk
authors.forename: Jolanta
authors.initials: J
authors.lastname: Kunert-Radek
mesh_terms: D000172:Acromegaly / Q000209:etiology / Q000378:metabolism*; D000236:Adenoma / Q000150:complications / Q000378:metabolism*; D000328:Adult; D005260:Female; D019382:Human Growth Hormone / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D010911:Pituitary Neoplasms / Q000150:complications / Q000378:metabolism*; D017481:Receptors, Somatostatin / Q000378:metabolism; D013972:Thyrotropin / Q000378:metabolism*; D055815:Young Adult
chemical_list: D017481:Receptors, Somatostatin; D019382:Human Growth Hormone; D013972:Thyrotropin
keywords: acromegaly; clinically nonfunctioning pituitary adenomas; silent thyrotropinoma