title: Lack of TSH inhibition by exogenous L-T4 in a patient with follicular thyroid carcinoma.
abstract: We report a case of a male patient thyroidectomized for follicular thyroid carcinoma and presenting extremely elevated serum thyrotropin levels under L-T4 suppressive therapy. Administration of L-T3 in increasing amounts resulted in a significant decrease of serum TSH levels. The nature of the possible molecular defects underlying this unusual condition and pitfalls arising from the failure of L-T4 therapy to inhibit TSH secretion in a patient in post-surgical follow-up for follicular carcinoma are discussed.
authors.affiliation: Endocrinology Unit, Tinchi Hospital, Matera, Italy. roccobruno1@virgilio.it
authors.forename: R
authors.initials: R
authors.lastname: Bruno
authors.forename: P
authors.initials: P
authors.lastname: Giannasio
authors.forename: P
authors.initials: P
authors.lastname: Bellitti
authors.forename: R
authors.initials: R
authors.lastname: Sinisi
authors.forename: F
authors.initials: F
authors.lastname: Arturi
authors.forename: D
authors.initials: D
authors.lastname: Russo
authors.forename: G
authors.initials: G
authors.lastname: Costante
mesh_terms: D018263:Adenocarcinoma, Follicular / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D013964:Thyroid Neoplasms / Q000378:metabolism*; D013972:Thyrotropin / Q000097:blood*; D013974:Thyroxine / Q000097:blood*; D014284:Triiodothyronine / Q000097:blood
chemical_list: D014284:Triiodothyronine; D013972:Thyrotropin; D013974:Thyroxine