A remarkable case of thyrotoxicosis initially caused by graves’ disease followed by a probable TSHoma – a case report

Abstract Background Graves’ disease is the commonest cause of thyrotoxicosis whilst thyrotropin (TSH)-producing pituitary adenomas (thyrotropinomas, TSHomas) are very rare and account for just 1–2% of all pituitary adenomas. Coexistence of a TSHoma and Graves’ disease has been very rarely reported. Here, we report a case of a patient whose initial presentation with primary thyrotoxicosis due to Graves’ disease, was subsequently followed by a relapse of thyrotoxicosis due to a probable TSHoma. Case A sixty-eight year old woman was referred to our department with classical features of thyrotoxicosis. Initial biochemistry confirmed hyperthyroxinaemia [free thyroxine (fT4) 20.4 pmol/L (reference range 7.0–16.0)] and a suppressed TSH [