A pituitary tumor is an abnormal growth on the pituitary gland, a small pea-sized organ located at the base of the brain behind the bridge of the nose. The pituitary gland produces nine hormones critical to normal body function. While technically not part of the brain, the pituitary gland’s location and the nature of tumors on the gland present many of the same challenges, risks, and dangers of other primary brain tumors.

Pituitary tumors are the third most common type of primary brain tumor, accounting for 9–12% of all such cases. Tumors arising from the pituitary gland itself are called adenomas or carcinomas. Pituitary adenomas are benign, slow-growing tumors. Carcinomas are a rare malignant form of pituitary adenoma.


Because the pituitary gland is responsible for the production of hormones key to proper body function, tumors often interfere with this production—either by limiting the amount of hormone produced or generating excessive amounts. Growth hormone (regulates body height and structure), prolactin (controls lactation, or milk production), sex hormones (control the menstrual cycle and other sexual functions), thyroid gland hormones (control the thyroid gland), adrenal gland hormones, and vasopressin (a hormone involved in water and electrolyte balance) are all examples of hormones that can be affected. Growing tumors can also push on surrounding structures, often resulting in headaches, behavioral changes, and vision problems.

Causes, Support, and More Information

The exact cause of pituitary tumors is not known. Treatment usually includes surgery to remove the tumor, though in some cases drug therapy may be used to reduce tumor size. Replacement hormone therapy is often prescribed following surgery and/or radiation.

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