title: A rare case of a thyrotropin-secreting pituitary tumor which responded to methimazole.
abstract: A 52-year-old Japanese male complained of palpitations and excessive sweating. He showed evidence of hyperthyroidism, but without suppression of the serum thyroid-stimulating hormone (TSH). On admission, the serum level of the alpha-subunit of TSH was elevated, but tests for thyroid autoantibodies were negative. The TSH response to thyrotropin-releasing hormone (TRH) was blunted. Imaging studies revealed a pituitary tumor 2 cm in diameter. Administration of methimazole lowered the serum levels of thyroid hormones, and elevated the serum level of TSH. These findings led to the diagnosis of a thyrotropin-secreting pituitary tumor. Immunohistochemical analysis and electron microscopic findings verified the diagnosis.
authors.affiliation: Department of Medicine, Koshigaya Hospital, Dokkyo University School of Medicine, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Inukai
authors.forename: Y
authors.initials: Y
authors.lastname: Fujiwara
authors.forename: Y
authors.initials: Y
authors.lastname: Aso
authors.forename: A
authors.initials: A
authors.lastname: Yamamoto
authors.forename: Y
authors.initials: Y
authors.lastname: Takemura
mesh_terms: D013956:Antithyroid Agents / Q000008:administration & dosage*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008713:Methimazole / Q000008:administration & dosage*; D008875:Middle Aged; D009376:Neoplasms, Hormone-Dependent / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D010911:Pituitary Neoplasms / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000378:metabolism* / Q000473:pathology; D011859:Radiography; D013972:Thyrotropin / Q000378:metabolism*
chemical_list: D013956:Antithyroid Agents; D008713:Methimazole; D013972:Thyrotropin