TSH-Secreting Adenomas

TSH-secreting (thyrotroph) adenomas are rare and account for less than 1% of all pituitary adenomas. They usually lead to excess production of thyroid hormone (hyperthyroidism), but can also be associated with long-standing primary hypothyroidism. TSH-secreting adenomas can co-secrete other hormones including growth hormone, prolactinoma, and gonadotropins and tend to have invasive features.

Symptoms

Common symptoms include anxiousness, tremulousness, restlessness, insomnia, weight loss, sweating, heat intolerance, and palpitations. Tumor mass effects are common as most patients have large tumors. A goiter may be present.

Treatment

Transsphenoidal surgery is the primary treatment for thyrotroph adenomas, and successful resection dependent on extension and size of the tumor. Patients with residual tumor will require radiation therapy or a trial of medical therapy with a somatostatin analog.

Left: TSH-secreting pituitary macroadenoma. Right: Regression in size of the TSH-secreting pituitary macroadenoma three months following the initiation of therapy with Sandostatin LAR.