The Endoscopic Endonasal Transsphenoidal Approach for Thyrotropin-Secreting Pituitary Adenomas: Single-Center Experience and Clinical Outcomes of 49 Patients.

Objective: To analyze surgical outcomes and tumor characteristics of 49 patients with thyrotropin-secreting pituitary adenoma, a rare functional pituitary adenoma subtype with challenging surgery, who underwent endoscopic endonasal transsphenoidal surgery.

Methods: In this single-center study, clinical, radiological, surgical, and endocrinological data of 49 patients diagnosed with thyrotropin-secreting pituitary adenoma were retrospectively reviewed.

Results: Mean tumor size was 21.12 mm (6 microadenomas, 41 macroadenomas, 2 giant adenomas). Cavernous sinus invasion was present in 12 (24.48%) patients. Tumor consistency was firm in 23 (46.93%) patients. Plurihormonal secretion characteristics were present in 9 patients (5 growth hormone + thyrotropin and 4 growth hormone + prolactin + thyrotropin). Mean follow-up duration was 51.73 months. Of the cases with firm tumors, 14 patients had a history of antithyroid drug use; there was no statistically significant correlation between the antithyroid medication and the firmness of the tumor. Gross total resection was achieved in 32 (65.30%) cases, near-total resection was achieved in 14 (28.57%) cases, and subtotal resection was achieved in 3 (6.12%) cases. The analysis showed that the negative effect of >2 cm tumor size and cavernous sinus invasion on resection rate was statistically significant (P < 0.001). Although early remission was achieved in 33 (67.34%) patients, 44 (89.79%) patients were in euthyroid state at >3 months' follow-up. Complications were 4 new-onset pituitary deficiencies, 3 cases of permanent diabetes insipidus, 1 thyrotoxic crisis, and 1 cerebrospinal fluid leak.

Conclusions: Endoscopic endonasal transsphenoidal surgery is the first-line treatment in thyrotropin-secreting pituitary adenoma and should be performed in a tertiary center. Gross total resection is the goal, and early diagnosis is essential for surgical success.