Long term treatment of a thyrotropin-secreting microadenoma with somatostatin analogues

Thyrotropin (TSH) secreting pituitary adenomas (TSH-omas) account for < 1% of all pituitary adenomas and are a rare cause of hyperthyroidism. The diagnosis is often made at the stage of macroadenoma because of the aggressive nature of the tumor and due to the fact that patients are mistakenly treated for more common primary hyperthyroidism for a long time. First line therapy is transsphenoidal resection of the tumor, which can cure one-third of the patients completely. However, if surgery is not possible or curative, pituitary radiotherapy and/or somatostatin analogs (SSA) can be useful. We report the case of a 54-year-old woman treated 20 years earlier for a mistakenly suspected primary hyperthyroidism. Given the persistence of symptoms she was studied further and was diagnosed with a thyrotropinoma. Despite the delay in diagnosis and prior thyroid ablation, a microadenoma was found. As transsphenoidal surgery was not considered effective, medical therapy with a somatostatin analogue was initiated. Currently, at four years of follow-up, the patient continues on this treatment and remains euthyroid and asymptomatic. We report a case of successful long-term treatment with SSA, after unsuccessful surgery. Arq Bras Endocrinol Metab. 2010;54(5):502-6