Q: What is the pituitary gland?
A: The pituitary gland is a small gland located behind the nasal sinuses and above the roof of the mouth at the base of the skull. It is connected to the hypothalamus, a part of the brain. Together, the two control the production of many of the important hormones in the body. The pituitary gland sits in a tight bony space and has little room to grow or expand when swollen or if there is a tumor.
The pituitary gland regulates the activity of most of the glands in the body, including the adrenal and thyroid glands and sexual hormone production (by regulating ovarian function in women and testicular function in men). The pituitary gland is considered to be the main control gland of the neuro-endocrine system.
The pituitary gland has two parts--the posterior pituitary (or back part) and the anterior pituitary (front part). The posterior pituitary makes the hormones called vasopressin and oxytocin:
Vasopressin (also called ADH [antidiuretic hormone]). This hormone allows the kidneys to retain healthy amounts of water rather than excreting it in urine. It can increase blood pressure.
Oxytocin. This female hormone helps the uterus contract during childbirth and helps the breasts release milk when a woman is nursing.
The anterior pituitary makes several kinds of hormones that, in turn, control other glands throughout the body:
Somatotropin. This is also known as the growth hormone. It helps a child's body grow, especially at puberty. It also helps the liver make insulin-like growth factor (IGF-1). IGF-1 causes bones and other tissues to grow.
Thyroid-stimulating hormone (also called TSH and thyrotropin). This hormone helps the thyroid gland to grow and to make and release the thyroid hormone.
Adrenocorticotropic hormone (ACTH). This hormone stimulates the adrenal gland so that it can make certain steroid hormones.
Luteinizing hormone (LH). This hormone regulates ovulation and menstruation in women and controls testosterone and the production of sperm in men.
Follicle-stimulating hormone (FSH). This hormone has functions similar to those of LH.
Prolactin. This hormone helps make milk in the female breast. Its function in men is not clear.
Q: What are pituitary tumors?
A: A pituitary tumor is a tumor that begins in the pituitary gland. Most pituitary tumors are not cancer. In fact, cancerous pituitary tumors are so rare that state and national cancer agencies keep no record of how many people get them each year. Benign (noncancerous) pituitary tumors are also rare. About 8,000 people get them each year.
Q: What are adenomas?
A: There are different kinds of pituitary tumors. However, nearly all of these tumors are adenomas (noncancerous tumors in the gland). Adenomas usually do not spread out of the pituitary gland. Still, they can greatly affect a person's health by pushing on other parts of the brain and by secreting excess amounts of hormones. Adenomas of the pituitary are classified in two ways:
Size. Microadenomas are tumors that are smaller than one centimeter, or about half an inch. Macroadenomas are tumors that are bigger than one centimeter. Microadenomas and macroadenomas can either make hormones (functional adenomas) or not make hormones (nonfunctional or null adenomas).
Hormones. Tumors are also grouped according to the type of hormone they produce. The types are named after the types of hormones the pituitary makes and include prolactin-producing adenomas, somatotropin-secreting adenomas, corticotropin-secreting adenomas, gonadotropin-secreting adenomas, thyrotropin-secreting adenomas, null cell adenomas (which do not produce any hormones), and adenomas of the mixed cell type.
Q: What are the risk factors for pituitary tumors?
A: Certain factors can make one person more likely to get a pituitary tumor than another person. These are called risk factors. In some cancers, doctors have identified risk factors that can be avoided, such as smoking or sun exposure. Doctors are not sure what exactly causes pituitary tumors and only one risk factor has been identified. Most people who get a pituitary tumor have no known risk factors.
The only proven risk factor for a pituitary tumor is multiple endocrine neoplasia, type 1. This is known as MEN1. MEN1 is a hereditary condition. People with it have a high risk of getting tumors of the pituitary, the parathyroid, and the pancreas. About half of all children of parents who carry the gene change for this rare syndrome will get MEN1.
Q: What are the symptoms of pituitary tumors?
A: People with a benign or cancerous pituitary tumor may have any or all of the following symptoms:
Double or blurred vision
Loss of ability to see out of the sides of the eyes (loss of peripheral vision)
Sudden loss of sight
Loss of consciousness
Unwanted weight loss or gain
Loss of menstrual periods
Loss of interest in sex
These symptoms could also be signs of other problems. A person who has them should see his or her doctor.
Pituitary tumors that affect hormones may cause a variety of symptoms, which are related to high hormone levels and production. These symptoms will be different in children than in adults. Growth hormone-secreting adenomas in children may cause:
Pain in joints
Being very tall (known as gigantism)
In adults, the growth hormone-secreting adenomas may cause:
Increase in hat, shoe, or ring size caused by growth of skull, hands, or feet
Deepening of voice
Change in facial structure
Other more rare kinds of pituitary tumors cause other symptoms. It is important for anyone who is experiencing any unusual symptoms to see his or her doctor.
Q: How are pituitary tumors treated?
A: In most cases, pituitary tumors are treated by surgery, radiation therapy, or by using drugs that block the tumor's ability to produce hormones.
Surgery. The goal of surgery is to remove the entire tumor from the pituitary gland. This is possible with most microadenomas, but may be less likely with macroadenomas. Sometimes the entire pituitary gland will have to be removed. Medications can provide the hormones that the pituitary gland used to produce.
Radiation. The goal of radiation therapy is to kill the tumor by using X-rays. This treatment is often used when a pituitary tumor cannot entirely be removed in surgery or when it comes back after surgery.
Hormone-blocking medicine. The goal of this therapy is to stop the tumors from overproducing hormones that are affecting other parts of the body. In some kinds of pituitary tumors, using medicine to stop hormone production or to block the effects of the overproduced hormone may be the only necessary treatment.
Doctors are always finding new ways to treat pituitary tumors. These new methods are tested in clinical trials. Before beginning treatment, a person should ask his or her doctor if there are any clinical trials he or she should consider.
Q: What are clinical trials?
A: Clinical trials are studies of new kinds of cancer treatments. Doctors conduct clinical trials to learn about how well new treatments work and what their side effects are. If they look promising, they are then compared to the current treatment to see if they work better or have fewer side effects. People who participate in these studies may benefit from access to new treatments before the FDA approves them. Participants also help further our understanding of cancer and help future cancer patients.
Q: Should everyone get a second opinion?
A: Many people with cancer get a second opinion from another doctor. There are many reasons to get a second opinion, including if the person is not comfortable with the treatment decision, if the type of cancer is rare, if there are different ways to treat the cancer, or if the person is not able to see a cancer expert.
Q: How can someone get a second opinion?
A: There are many ways to get a second opinion:
The person's primary doctor may be able to recommend a specialist, such as a surgeon, medical oncologist, or radiation oncologist. Sometimes these doctors work together at cancer centers or programs.
The Cancer Information Service (800-4-CANCER or 800-422-6237) informs callers about treatment facilities, including cancer centers and other programs supported by the National Cancer Institute.
Patients can get names of doctors from their local medical society, a nearby hospital, a medical school, or local cancer advocacy groups, as well as from other people who have had that type of cancer.