Thyrotrophin-Secreting Pituitary Adenomas

Thyrotrophin-secreting adenomas are the least prevalent among pituitary tumors. Patients present with signs and symptoms of thyrotoxicosis, associated with high serum levels of thyroid hormones, and elevated or inappropriately normal levels of thyroid-stimulating hormone. As most are macroadenomas, clinical manifestations related to compression of neighboring structures are often present. Cosecretion of growth hormone and prolactin with associated clinical symptoms is common. Pituitary microsurgery is the cornerstone of treatment, offering a good chance of remission for small tumors, and improved symptoms by debulking larger tumors. Somatostatin receptor ligands are recommended as second-line treatment after unsuccessful surgery, due to their high effectiveness in controlling tumoral hypersecretion and tumor growth. Radiotherapy is reserved for the occasional patients unresponsive to treatment with somatostatin receptor ligands. With the availability of improved diagnostic and therapeutic tools, these rare pituitary tumors may be successfully controlled in most patients.