Case of hyperthyroidism due to a chromophobe adenoma

A A 23-year-old man with secondary hypogonadism was also found to be thyrotoxic. Results of thyroid function tests were in the hyperthyroid range but the serum TSH was inappropriately high. A pituitary tumour was demonstrated and following hypophysectomy he became biochemically hypothyroid. Evidence is presented and discussed that his hyperthyroidism was due to excessive TSH production by the pituitary tumour.