Pituitary Tumors Overview
An Abnormal Growth in Your Pituitary Gland
Pituitary tumors are abnormal growths that can develop in your pituitary gland, causing excessive production of certain hormones.
Your pituitary gland is a pea-sized gland that's located at the base of your brain.
Although it's small, your pituitary gland is mighty—it's known as the "master gland" because it's responsible for regulating the activities of the other glands in your endocrine system. Your pituitary gland releases hormones that regulate your thyroid, for example.
The pituitary gland produces several hormones. However, the most important hormones it produces that are related to pituitary tumors are:
- adrenocorticotropic hormone (ACTH)
- growth hormone (GH)
- thyroid-stimulating hormone (TSH)
Fortunately, most pituitary tumors are non-cancerous growths (called adenomas), which means they won't spread to other areas of your brain or surrounding tissues.
Pituitary tumors can be classified into 2 categories:
- Microadenomas: smaller pituitary tumors (smaller than 10 mm)
- Macroadenomas: larger pituitary tumors (bigger than 10 mm)
Both microadenomas and macroadenomas cause overproduction of the hormones mentioned above—what hormones are overproduced depends on where the tumor is located. That's because different hormones are produced in different areas of the pituitary.
The main types of pituitary tumors are:
- adrenocorticotropic hormone-secreting tumors: ACTH tumors produce adrenocorticotropin, a hormone that stimulates your adrenal glands (the triangular-shaped glands on top of your kidneys) to produce cortisol (another hormone). You can develop Cushing's disease as a result of ACTH causing too much cortisol.
- growth hormone-secreting tumors: GH tumors produce excess growth hormone, which can cause acromegaly.
- prolactin-secreting tumors: Known as prolactinomas, these tumors can decrease levels of sex hormones due to an excessive production of prolactin.
- thyroid-stimulating hormone-secreting tumors: TSH tumors can cause your thyroid to make too much thyroxine (a main thyroid hormone). Although this type of tumor is rare, it can cause hyperthyroidism, which can put your body's metabolism into overdrive.
Pituitary tumors can cause fatigue, unexplained weight loss or weight gain, and, in extreme cases, blindness. But pituitary tumors don't always cause symptoms. It's possible for you to have a pituitary tumor but never get diagnosed.
In this article series, we'll review the common symptoms, causes, risk factors, and treatments for pituitary tumors.
- Jameson JL, De Groot LJ, eds. Endocrinology: Adult and Pediatric. Volume II. Philadelphia, PA: Saunders Elsevier; 2010.
- Pituitary tumor page. MedlinePlus Web site. Available at: http://www.nlm.nih.gov/medlineplus/ency/article/000704.htm. November 15, 2010. Accessed November 30, 2010.
- Pituitary tumors page. Mayo Clinic Web site. Available at: http://www.mayoclinic.com/health/pituitary-tumors/DS00533. June 5, 2010. Accessed November 30, 2010.