Pituitary adenomas – are benign tumors that develop in the pituitary endocrine gland, a structure located at the base of the brain that secretes key hormones of the endocrine system. A part of the adenomas produce endocrine diseases through an exaggerated secretion of a certain type of hormone: Cushing disease, acromegaly etc. Other part of the adenomas are non-secreting, but, the large ones can compress the optic nerves affecting vision.