title: Thyrotropin-secreting pituitary tumours: significance of "atypical adenomas" in a series of 10 patients and association with Hashimoto thyroiditis as a cause of delay in diagnosis.
abstract: BACKGROUND
  Thyrotropin-secreting adenomas (TSH-As) are rare and, according to the World Health Organization criteria (WHO 2004), a significant proportion of them present features of atypical adenomas at the time of diagnosis.
  
  
  OBJECTIVE
  To determine the frequency of "atypical adenomas" and the significance of this definition as regards follow-up. To investigate their possible association with Hashimoto thyroiditis, leading to a delay in diagnosis.
  
  
  METHODS
  Case notes for patients who underwent trans-sphenoidal surgery between 1992 and 2006 were retrieved. Follow-up ranged from 6 to 180 months.
  
  
  RESULTS
  Ten cases of TSH-As out of 908 pituitary adenomas were selected. Before surgery, eight patients had hyperthyroidism, one was euthyroid and another one showed hypothyroidism associated with Hashimoto thyroiditis. All cases were macroadenomas; six of them were invasive. Three cases met the criteria for classification as atypical. In none of the cases, including the three "atypical adenomas", were clinical or radiological signs of recurrence observed.
  
  
  CONCLUSIONS
  The three cases with features of atypical adenoma did not recur or metastasise, suggesting that, at least in the present series, a strict relationship between the morphological criteria for diagnosing atypical adenomas and biological behaviour may be sometimes lacking. Furthermore, the casual association of TSH-As with Hashimoto thyroiditis may led to an adjunctive delay in diagnosis, because of low thyroid hormone levels.
authors.affiliation: Section of Pathology, Department of Haematology and Oncology of the University of Bologna, Bellaria Hospital, Bologna, Italy. marucci@ausl.bologna.it
authors.forename: G
authors.initials: G
authors.lastname: Marucci
authors.forename: M
authors.initials: M
authors.lastname: Faustini-Fustini
authors.forename: A
authors.initials: A
authors.lastname: Righi
authors.forename: E
authors.initials: E
authors.lastname: Pasquini
authors.forename: G
authors.initials: G
authors.lastname: Frank
authors.forename: R
authors.initials: R
authors.lastname: Agati
authors.forename: M P
authors.initials: MP
authors.lastname: Foschini
mesh_terms: D000236:Adenoma / Q000150:complications / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D000328:Adult; D000368:Aged; D005260:Female; D005500:Follow-Up Studies; D050031:Hashimoto Disease / Q000150:complications*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D010911:Pituitary Neoplasms / Q000150:complications / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D013972:Thyrotropin / Q000378:metabolism*; D055815:Young Adult
chemical_list: D013972:Thyrotropin