Surgical Outcome and Treatment of Thyrotropin-Secreting Pituitary Tumors in a Tertiary Referral Center

Abstract

Objective: Thyrotropin (TSH)-secreting pituitary tumors are rare and typically present with hyperthyroidism. Here we report the diagnosis, treatment, and surgical outcomes in a series of patients with TSH-secreting pituitary tumors in a tertiary referral center.

Methods: Descriptive retrospective study that included all patients with TSH-secreting pituitary tumors who underwent transsphenoidal surgery in the endocrinology and nutrition unit of the Virgen del Rocío University Hospital (Seville, Spain) between 2004 and 2016.

Results: The mean age at diagnosis was 42.8 ± 17 years. The mean time from onset of symptoms to diagnosis was 13 ± 10 months. Four patients displayed symptoms indicating hyperthyroidism (1 suffered from tachycardia); 3 patients showed symptoms because of mass effect (visual impairment and headache) and 3 patients were diagnosed based on incidental findings after routine blood tests (high free thyroxine levels). Eight patients had macroadenomas, and 2 patients had microadenomas. Five patients underwent conventional pituitary surgery, and 5 patients underwent expanded endoscopic transsphenoidal surgery. Six patients achieved cure after surgery. The other patients received radiotherapy and/or treatment with somatostatin analogs. Analysis of somatostatin receptor (SSTR) expression by immunohistochemistry could be performed in 6 tumors.

Conclusions: Our results confirm the clinical and hormonal heterogeneity caused by TSH-secreting pituitary adenomas. Surgery is considered the first choice of treatment for these tumors. We observed surgical cure rates similar to those reported in recent published series. SSTR2 and SSTR3 are highly expressed in TSH-secreting pituitary adenomas. Our results suggest that somatostatin analog treatment may be also helpful in the treatment of TSH-secreting pituitary adenomas.

Keywords: SSTRs; Somatostatin receptors; TSH-Secreting pituitary tumors.