title: Thyrotropin-secreting adenoma in a patient with primary hypothyroidism.
abstract: OBJECTIVE
  To describe a patient who developed a thyrotropin (TSH)-secreting adenoma in the setting of primary hypothyroidism.
  
  
  METHODS
  We report the clinical, laboratory, and radiologic findings of a patient with a history of primary hypothyroidism who presented with headache, a bitemporal visual field deficit, and elevated TSH despite long-term levothyroxine therapy. We discuss the diagnostic challenges of this case and review the relevant literature.
  
  
  RESULTS
  A 54 year old woman with a history of primary hypothyroidism presented with a 3-year history of headache and a week of worsening vision. Imaging revealed a heterogeneous sellar mass elevating the optic chiasm. Her serum TSH was 46.5 mIU/L and free thyroxine concentration was 0.1 ng/dL. The differential diagnosis included pituitary hyperplasia and a TSH-secreting adenoma in a patient with primary hypothyroidism. The pathologic characteristics of the tumor were consistent with the latter.
  
  
  CONCLUSIONS
  In a patient with an elevated TSH concentration and a previous diagnosis of hypothyroidism, it is important to consider other entities besides medication noncompliance. TSH-secreting adenomas can also cause elevated levels of TSH.
authors.affiliation: Division of Endocrinology, UT Southwestern Medical Center at Dallas, Dallas, Texas 75390-9073, USA. Dr.AKMyers@gmail.com
authors.forename: Alyson
authors.initials: A
authors.lastname: Myers
authors.forename: Kimmo J
authors.initials: KJ
authors.lastname: Hatanpaa
authors.forename: Christopher
authors.initials: C
authors.lastname: Madden
authors.forename: Ildiko
authors.initials: I
authors.lastname: Lingvay
mesh_terms: D000236:Adenoma / Q000097:blood / Q000150:complications* / Q000175:diagnosis* / Q000378:metabolism; D003937:Diagnosis, Differential; D005260:Female; D006261:Headache / Q000209:etiology; D006801:Humans; D007037:Hypothyroidism / Q000150:complications*; D008875:Middle Aged; D009897:Optic Chiasm / Q000473:pathology*; D010902:Pituitary Gland / Q000473:pathology; D010911:Pituitary Neoplasms / Q000097:blood / Q000150:complications* / Q000175:diagnosis* / Q000378:metabolism; D013972:Thyrotropin / Q000097:blood / Q000378:metabolism*; D013974:Thyroxine / Q000097:blood; D014786:Vision Disorders / Q000209:etiology; D014794:Visual Fields
chemical_list: D013972:Thyrotropin; D013974:Thyroxine