Pituitary hyperplasia resulting from primary hypothyroidism mimicking macroadenomas

Br J Neurosurg. 1999 Apr;13(2):138-42. doi: 10.1080/02688699943880.


Three patients presented with clinical and imaging features suggestive of a primary functional pituitary adenoma. Surprisingly, thyroid function testing revealed co-existing primary hypothyroidism. The pituitary tumours represented hyperplasia of anterior pituitary thyrotrophs secondary to hypothyroidism. Complete regression was achieved with thyroxine replacement therapy. Careful attention should be paid to differentiating this condition from prolactinoma or the rare TSH producing adenoma.

Publication types

  • Case Reports

MeSH terms

  • Adenoma / diagnosis*
  • Adolescent
  • Adult
  • Child
  • Diagnosis, Differential
  • Female
  • Humans
  • Hyperplasia / diagnosis
  • Hypothyroidism / diagnosis*
  • Magnetic Resonance Imaging
  • Pituitary Neoplasms / diagnosis*
  • Thyroid Gland / pathology*
  • Thyroxine / therapeutic use
  • Tomography, X-Ray Computed


  • Thyroxine