PITUITARY TUMORS
● These account for approximately 9% of primary brain tumors.
● They can be divided into functioning and nonfunctioning tumors.
A) Functioning tumors are usually microadenomas (< 1 cm in diameter) that secrete hormones and produce specific endocrine syndromes(e.g.,acromegaly for growth hormone-secreting tumors, Cushing syndrome for adrenocorticotropic hormone [ACTH]-secreting tumors, and galactorrhea, amenorrhea, and infertility for prolactin-secreting tumors).
B ) Nonfunctioning pituitary tumors tend to be macroadenomas (> 1 cm) that produce symptoms by mass effect, giving rise to headaches, visual impairment (such as bitemporal hemianopia), and hypopituitarism.