Nodular Thyroid Disease and Papillary Thyroid Carcinoma in Functional Pituitary Adenomas

ABSTRACT

Objective: Increased frequency of nodular thyroid disease has been reported in acromegalic patients. Recent studies have also demonstrated an increased co-existence of nodular thyroid di- sease with Cushing’s disease and prolactinoma. In this study, we evaluated the frequency and outcomes of nodular thyroid disease in each type of functional pituitary adenoma.

Material and Methods: A total of 232 patients diagnosed with acromegaly (n=138), prolactinoma (n=59) or Cushing’s disease (n=35) were included in this retrospective observational study. The frequency of nodular thyroid disease, fine-needle aspiration re- sults, and the frequency of papillary thyroid carcinoma were com- pared in each group. Factors related to nodule development were evaluated in functional pituitary adenoma patients with or without nodules.

Results: Nodular thyroid disease frequency was higher in pati- ents with acromegaly (69%) compared to those with prolactinoma (36%) or Cushing’s disease (34%) (p<0.001). Fine-needle aspi- ration results and PTC frequencies were similar between the gro- ups. In comparison to patients without nodules (n=104), those with nodules (n=128) were older (p=0.01) and had a higher inci- dence of glucose metabolism disorders (p=0.006). Insulin-like growth factor-1 levels were higher in acromegalic patients with no- dular thyroid disease (p=0.01). There was no relationship between nodule formation and baseline prolactin or cortisol/adrenocorticot- ropic hormone levels in the patients with prolactinomas and Cus- hing’s disease, respectively.

Conclusion: Although nodular thyroid disease was more common in acromegalic patients, its incidence in patients with prolactinoma and Cushing’s disease were higher than previously reported in our country (23.5%). The most important factors affecting nodule for- mation in functional pituitary adenoma patients were glucose me- tabolism disorders and age. Although a higher frequency of PTC has been reported in acromegalic patients, it was similar for all functional pituitary adenoma patients in our study.