Thyrotropin-secreting pituitary adenomas.
Normal or elevated thyrotropin (TSH) levels in hyperthyroid patients are characteristic of rare TSH-secreting pituitary adenoma (TSH-oma), which is easily detectable by computed tomographic (CT) scan or magnetic resonance imaging (MRI). Other diagnostic aids are an absent/impaired TSH response to thyrotropin-releasing hormone (TRH), discrepant TSH and alpha-subunit responses to TRH, high sex hormone-binding globulin (SHBG) levels, high alpha-subunit levels, and a high alpha-subunit/TSH molar ratio. Familial studies help rule out thyroid hormone resistance (RTH). Surgical removal of TSH-oma leads to clinical and biochemical remission in most patients. In surgical failures, radiotherapy and octreotide treatment have a high success rate. Undetectable TSH 1 week postsurgery suggests a definitive cure, backed up by tests for cosecreted hormones from the adenoma and dynamic tests of TSH suppression.
Beck-Peccoz
P
P
Institute of Endocrine Sciences, University of Milan, Ospedale Maggiore IRCCS, Italy.
Persani
L
L
Mantovani
S
S
Cortelazzi
D
D
Asteria
C
C
D000236:Adenoma / Q000175:diagnosis / Q000378:metabolism* / Q000628:therapy; D003937:Diagnosis, Differential; D006801:Humans; D010911:Pituitary Neoplasms / Q000175:diagnosis / Q000378:metabolism* / Q000628:therapy; D013972:Thyrotropin / Q000378:metabolism*
D013972:Thyrotropin