Thyroid Stimulating Hormone Secreting Adenoma (TSHoma)

Pituitary thyroid stimulating hormone (TSH) hypersecreting adenomas are rarer than any other hypersecretory pituitary adenoma. The etiology of these tumors is not known. TSHomas cause central hyperthyroidism, with elevation of the thyroid hormones without suppression of TSH. Although reported to occur at most ages, there is a higher prevalence with increasing age. Most patients present with macroadenomas (>1 cm), headaches, and visual changes associated with tumor enlargement and optic nerve pathway compression. Others present with symptoms of thyrotoxicosis. Early diagnosis and treatment is recognized as the best means of avoiding complications such as vision loss, cardiac arrhythmias, or bone loss. New imaging modalities have improved diagnosis and made early treatment possible. Treatment has two goals: normalization of TSH hypersecretion and tumor control. Primary therapy is aimed at tumor removal in order to normalize TSH, but medical therapy may be indicated if hypersecretory tumor remnants remain or there is tumor regrowth. There is little data regarding long-term outcomes, late effects, or quality of life. This is likely related to the rarity of the disease.