The pituitary gland is a pea-sized gland at the base of the brain, just above the back of the nose. It makes different hormones that affect the way many parts of the body work.

Most pituitary tumors are benign (not cancer), and are called pituitary adenomas. These tumors grow very slowly. They do not spread from the pituitary gland to distant parts of the body, but they sometimes spread to the bones of the skull or sinus cavity near the pituitary gland. A very small number of pituitary tumors are malignant (cancer) and can spread to distant parts of the body.

Most pituitary tumors make more hormones than normal pituitary cells. The extra hormones may cause signs or symptoms of disease. The signs and symptoms depend on which hormone is being made.

A family history of multiple endocrine neoplasia type 1 (MEN1) syndrome, Carney complex, or isolated familial acromegaly increases the risk of pituitary tumors.