ON THIS PAGE: You will find some basic information about this disease and the parts of the body it may affect. This is the first page of Cancer.Net’s Guide to Pituitary Gland Tumor. Use the menu to see other pages. Think of that menu as a roadmap for this entire guide.
About the pituitary gland
The pituitary gland is a small, pea-sized gland located behind the bridge of the nose and near the brain. It is a part of the endocrine system, which regulates hormones in the body. The pituitary gland is often called the "master endocrine gland," because it releases hormones that control other glands in the body that affect many bodily functions. The pituitary gland is controlled by the hypothalamus, a small structure in the brain.
A pituitary gland has 2 lobes, the anterior (front) and the posterior (back). Each lobe is responsible for releasing specific hormones.
Hormones released by the anterior pituitary lobe
Thyroid stimulating hormone (TSH) stimulates the thyroid gland, which helps regulate the body’s metabolism.
Adrenocorticotrophic hormone (ACTH) controls the hormones released by the adrenal gland, which supports blood pressure, metabolism, and the body's response to stress.
Gonadotropins, a family of hormones that include follicle stimulating hormone (FSH) and luteinizing hormone (LH), which stimulate production of sperm in the testicles or eggs in the ovaries. Gonadotropins also regulate the menstrual cycle.
Growth hormone (GH) promotes growth of the long bones in the arms and legs, and thickens the skull and bones of the spine. GH also causes the tissue over the bones to thicken.
Prolactin is normally low in everyone but levels rise when needed to stimulate breast milk production, called lactation, after childbirth.
Lipotropin stimulates the movement of fat from the body to the bloodstream.
Melanocyte stimulating hormone (MSH) regulates the production of melanin, the pigment in skin.
Hormones released by the posterior pituitary lobe
Oxytocin stimulates contraction of the uterus during childbirth and the flow of milk during breastfeeding.
Antidiuretic hormone, also known as vasopressin, increases reabsorption of water by the kidneys and allows a person to stay hydrated.
Types of tumors in the pituitary gland
Cancer begins when healthy cells change and grow out of control, forming a mass called a tumor. A pituitary gland tumor can be cancerous or benign. A cancerous tumor is malignant, meaning it can grow and spread to other parts of the body. A benign tumor means the tumor can grow but will not spread.
Most often, pituitary gland tumors are benign growths called pituitary adenomas. But a pituitary gland tumor can occasionally act like a cancerous tumor by growing into nearby tissue and structures, or rarely, spreading to other parts of the body.
Pituitary gland tumors are not brain tumors. The pituitary gland is located under the brain and is separate from the brain. Pituitary gland tumors are medically classified as "endocrine tumors."
Both benign and cancerous tumors in this gland can create very serious medical problems by interfering with the normal endocrine function of the pituitary gland. In some cases, this is because the tumor starts in cells that make hormones, so the tumor itself can make too many hormones. Pituitary tumors that produce hormones are called "functional tumors."
In other instances, a pituitary tumor can cause the gland to produce too few hormones. Also, if a pituitary tumor presses on nearby structures, such as the nearby optic nerves in the eye, it can limit a person’s vision.
The next section in this guide is Statistics. It helps explain the number of people who are diagnosed with a pituitary gland tumor and general survival rates. Use the menu to choose a different section to read in this guide.