title: TSH-induced hyperthyroidism caused by a pituitary tumor.
abstract: BACKGROUND
  A 45-year-old man presented with frontal headache and visual disturbances to our clinic. For the previous 5 years, he had been receiving treatment for long-lasting mild hyperthyroidism with antithyroid therapy, but therapy had not been carefully followed. During the last 2 years he had also complained of erectile dysfunction and loss of libido. On physical examination, he had a small goiter, normal skin, no Graves' ophthalmopathy, normal BMI, and reduced testis volume and pubic hair.
  
  
  METHODS
  Serum levels of free T3 and T4, serum prolactin, testosterone, serum gonadotropins, insulin-like growth factor 1, adrenocorticotropic hormone, and cortisol were measured. MRI scan, TSH-releasing hormone test, and T3 suppression test were carried out. Levels of pituitary glycoprotein hormone alpha-subunit and sex-hormone-binding protein were also measured.
  
  
  METHODS
  Hyperthyroidism caused by a mixed pituitary adenoma that secretes prolactin and TSH.
  
  
  RESULTS
  Trans-sphenoidal resection of the pituitary tumor. After surgery, T3 suppression test failed to completely suppress TSH secretion, which suggested a persistence of residual adenomatous cells. Hyperthyroidism and hypogonadism recurred after 5 years, therefore, treatment with lanreotide was initiated, and resulted in complete resolution of signs and symptoms of the disease.
authors.affiliation: Department of Medical Sciences, University of Milan, Milan, Italy. paolo.beckpeccoz@unimi.it
authors.forename: Paolo
authors.initials: P
authors.lastname: Beck-Peccoz
authors.forename: Luca
authors.initials: L
authors.lastname: Persani
mesh_terms: D000236:Adenoma / Q000150:complications* / Q000175:diagnosis / Q000378:metabolism / Q000601:surgery; D013956:Antithyroid Agents / Q000627:therapeutic use; D003937:Diagnosis, Differential; D006801:Humans; D006980:Hyperthyroidism / Q000175:diagnosis / Q000188:drug therapy / Q000209:etiology* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D015282:Octreotide / Q000627:therapeutic use; D010456:Peptides, Cyclic / Q000627:therapeutic use; D010911:Pituitary Neoplasms / Q000150:complications* / Q000175:diagnosis / Q000378:metabolism / Q000601:surgery; D013004:Somatostatin / Q000031:analogs & derivatives / Q000627:therapeutic use; D013972:Thyrotropin / Q000378:metabolism*
chemical_list: D013956:Antithyroid Agents; D010456:Peptides, Cyclic; C060347:lanreotide; D013004:Somatostatin; D013972:Thyrotropin; D015282:Octreotide