[Atypical pituitary tumors]

Abstract

The significant progress made in recent years, especially in the field of imaging procedures and immunocytochemistry, has caused great improvement in the identification and differentiation of less known pituitary tumours. Thyrotropin (TSH)-secreting adenomas constitute about 1-2% of all pituitary tumours and their presence leads to central hyperthyroidism. This condition is characterised by a diffuse goiter, elevated circulating levels of free thyroid hormones and a nonsuppressed serum TSH. Gonadotropin-secreting tumours in rare cases may result in ovarian hyperstimulation, testicular enlargement or precocious puberty The vast majority of clinically non-functioning pituitary tumours are gonadotroph-cell adenomas accounting for 40 to 50% of all pituitary macroadenomas. True non-functioning pituitary tumours may cause, as a result of their mass effect, optic chiasm compression or deficient hormone secretion. Transsphenoidal surgery with or without external irradiation is considered the treatment of choice of all the discussed pituitary tumours. This manuscript was aimed to provide an overview of the contemporary etiopathogenesis, diagnosis and treatment of thyrotropin- and gonadotropin-secreting and non-functioning pituitary adenomas.