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 coexistence of nodular thyroid disease 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 results, and the frequency of papillary thyroid carcinoma were compared 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 patients with acromegaly (69%) compared to those with prolactinoma (36%) or Cushing's disease (34%) (p<0.001). Fine-needle aspiration results and PTC frequencies were similar between the groups. In comparison to patients without nodules (n=104), those with nodules (n=128) were older (p=0.01) and had a higher incidence of glucose metabolism disorders (p=0.006). Insulin-like growth factor-1 levels were higher in acromegalic patients with nodular thyroid disease (p=0.01). There was no relationship between nodule formation and baseline prolactin or cortisol/adrenocorticotropic hormone levels in the patients with prolactinomas and Cushing'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 formation in functional pituitary adenoma patients were glucose metabolism 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.