Definition:

Pituitary TSH hypersecretion is disease of the anterior portion of the pituitary resulting in hypersecretion of thyroid stimulating hormone (TSH). It includes two forms of central hyperthyroidism, i.e. TSH-secreting pituitary adenoma (TSHoma) and resistance to thyroid hormone action (RTH). The incidence of hyperthyroidism due to a TSHoma is extremely low, 1-2% of all cases of hyperthyroidism. Most of the tumors are macroadenomas usually presenting with symptoms such as headache and/or visual field impairment while the symptoms of hyperthyroidism seem to be milder compared with those caused by primary hyperthyroidism. First-line treatment of TSHoma is pituitary adenomectomy followed by irradiation in the case of surgical failure. However, medical treatment with somatostatin analogs, such as octreotide and lanreotide, are effective in reducing TSH secretion.