A pituitary tumor is a growth of abnormal cells in the tissues of the pea-sized organ at the center of the brain, which is sometimes called the “master endocrine gland” because it makes hormones that affect the way many parts of the body work.
Pituitary tumors are divided into three groups: benign pituitary adenomas, invasive pituitary adenomas, and pituitary carcinomas. The first two groups of tumors are benign, while pituitary carcinomas are malignant and spread into other areas of the central nervous system or beyond. Very few pituitary tumors are malignant.
Having certain genetic conditions increases the risk of developing a pituitary tumor. Those include multiple endocrine neoplasia type 1 (MEN1) syndrome, Carney complex, and isolated familial acromegaly.Pituitary Tumors Treatment (PDQ®)
Source: National Cancer Institute