TSH-secreting tumours are extremely rare and are thought to account for approximately 1% of pituitary neoplasms. TSHomas have been associated with both hyperthyroidism and hypothyroidism.
A very small minority of pituitary tumours secrete the gonadotrophins (LH/FSH). These types of tumour are most commonly seen in older men. It is estimated that approximately 2/3 of 'functionless' tumours show evidence of gonadotrophin production.