Clinical characteristics and thyroid hormone dynamics of thyrotropin-secreting pituitary adenomas at a single institution.

Abstract

Thyrotropin-secreting pituitary adenomas (TSPA) are extremely rare pituitary adenomas; their perioperative thyroid hormone dynamics have not been completely elucidated. Here, we investigated the clinical characteristics, perioperative findings, and thyroid hormone dynamics of TSPA at a single institution. We enrolled 11 patients who underwent transsphenoidal surgery (TSS) for TSPA during 2005-2019 at Hiroshima University Hospital (TSPA group) and 24 patients who underwent TSS for nonfunctioning pituitary adenomas (NFPA) in 2019 (NFPA group; for comparison). Their clinical characteristics, operative findings, and thyroid hormone dynamics, including serum thyroid-stimulating hormone (TSH), free triiodothyronine (FT3), and free thyroxine (FT4), were retrospectively analyzed. The NFPA group demonstrated a slight temporary decrease in serum TSH/ FT3/ FT4 levels on day 1 postoperatively and improvement in the levels on day 4 postoperatively. In contrast, the serum TSH level in the TSPA group demonstrated a marked decrease on day 1 postoperatively but improved on day 7 postoperatively. The serum FT3 level was also markedly decreased on day 1 postoperatively but remained within the normal range. The serum FT4 level revealed a gradual decrease until day 21 postoperatively and then recovered within the normal range 3 months postoperatively. There was no significant difference in the frequency of decline in serum FT4 level between the two groups; no patients required thyroid hormonal replacement 3 months postoperatively. Despite a variable degree of transient hypothyroidism, all patients had a normal thyroid function after 3 months follow-up.