title: Thyrotropin-secreting pituitary adenoma: a case report.
abstract: We report a 44-year-old male with a thyrotropin (TSH)-secreting pituitary adenoma. Based serum free triiodothyronine (FT3, 12.1 pmol/l) and free thyroxine (FT4, 28 pmol/l) were increased with normal basal TSH (3.1 mU/l). There was impaired TSH response to thyrotropin releasing hormone (TRH) test. Serum TSH was suppressed to 59% of the basal level after oral administration of 1.4 mg 3,3'-5-triiodothyroacetic acid (triac), whereas no suppression was observed after 75 micrograms daily administration of triiodothyronine (T3). Serum concentrations of alpha-subunit of TSH (TSH-alpha) and TSH-alpha/TSH molar ratio were high, being 1.95 micrograms/l, and 4.4, respectively. Pituitary CT and MRI scan showed the presence of a macroadenoma in the anterior lobe of the pituitary gland. Histopathology of the excised pituitary confirmed the diagnosis of a TSH-producing adenoma. A positive correlation between TSH and FT3 (r = 0.66, P less than 0.01) or FT4 (r = 0.54, P less than 0.01) was observed in serial sera obtained before and after operation.
authors.affiliation: Department of Internal Medicine, Takayama Red Cross Hospital, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Nagai
authors.forename: S
authors.initials: S
authors.lastname: Sakata
authors.forename: C C
authors.initials: CC
authors.lastname: Wu
authors.forename: H
authors.initials: H
authors.lastname: Wada
authors.forename: K
authors.initials: K
authors.lastname: Yokoyama
authors.forename: M
authors.initials: M
authors.lastname: Takada
authors.forename: T
authors.initials: T
authors.lastname: Kashiwai
authors.forename: N
authors.initials: N
authors.lastname: Tokimitsu
mesh_terms: D000328:Adult; D006801:Humans; D006980:Hyperthyroidism / Q000097:blood / Q000209:etiology*; D008297:Male; D010911:Pituitary Neoplasms / Q000097:blood / Q000150:complications / Q000378:metabolism*; D013972:Thyrotropin / Q000097:blood / Q000378:metabolism*; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood
chemical_list: D014284:Triiodothyronine; D013972:Thyrotropin; D013974:Thyroxine