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The pituitary gland is a small bean-shaped gland located at the base of your brain, somewhat behind your nose and between your ears. Despite its size, the gland influences nearly every part of your body. Its hormones help regulate important functions, such as growth, blood pressure and reproduction.

Pituitary tumors are abnormal growths that develop in the pituitary gland. Sometimes pituitary tumors can produce excess amounts of hormones. Other times, pituitary tumors can restrict the pituitary gland, causing it to produce lower levels of hormones (hypopituitarism).

Most pituitary tumors are noncancerous (benign), nonspreading growths (adenomas). Adenomas remain confined to the pituitary gland or surrounding tissues and don't spread to other parts of your body.

Treatment for pituitary tumors may involve surgery to remove the tumor. Medications or radiation therapy to control growth of a pituitary tumor also may be an option. You may also need medications to correct excess or deficient hormone production.

Pituitary tumors that produce hormones are called functioning tumors. Tumors that don't produce hormones are known as nonfunctioning pituitary tumors.

Different types of functioning tumors can develop in your pituitary gland, each causing specific signs and symptoms:

• Adrenocorticotropic hormone-producing tumors. These pituitary tumors produce the hormone adrenocorticotropin, which stimulates your adrenal glands to make the hormone cortisol. When your adrenal glands produce too much cortisol, a condition called Cushing's syndrome occurs. Signs and symptoms of Cushing's syndrome may include weight gain around your midsection and upper back, exaggerated facial roundness, a characteristic hump on the upper part of your back, high blood pressure, muscle weakness and thinning of your skin.
• Growth hormone-producing tumors. These tumors produce excess growth hormone. The physical effects from excess growth hormone (acromegaly) may include coarsened facial features, enlarged hands and feet, high blood pressure and heart problems. Accelerated and excessive growth (gigantism) may occur in children.

• Prolactin-producing tumors. Overproduction of prolactin from a pituitary tumor (prolactinoma) can cause a decrease in normal levels of sex hormones — estrogen in women and testosterone in men. Excessive prolactin in the blood (hyperprolactinemia) can affect men and women differently.

  In women, prolactinoma may cause irregular menstrual periods (oligomenorrhea), lack of menstrual periods (amenorrhea) and milky discharge from the breasts (galactorrhea).

  In men, a prolactin-producing tumor may cause male hypogonadism, which may involve signs and symptoms such as enlarged breasts (gynecomastia), erectile dysfunction (ED) or impotence, infertility, decrease in body hair, and loss of interest in sexual activity.

• Thyroid-stimulating hormone-producing tumors. When a pituitary tumor overproduces thyroid-stimulating hormone, your thyroid gland makes too much of the hormone thyroxine. This is a rare cause of hyperthyroidism, or overactive thyroid disease. Hyperthyroidism can accelerate your body's metabolism, causing sudden weight loss, a rapid or irregular heartbeat, and nervousness or irritability.

Functioning and nonfunctioning pituitary tumors may cause other signs and symptoms, including:

• Headache
• Vision changes, such as decreased peripheral vision or double vision
• Seizures
• Clear, watery nasal drainage
• Hair loss
• Cold intolerance
• Constipation
• Irritability
• Weakness
• Fatigue
• Nausea
• Vomiting
• Low blood pressure
• Unintended weight loss or gain

The pituitary gland is part of your endocrine system, which consists of glands that produce hormones that regulate processes throughout your body. Besides the pituitary gland, the endocrine system includes the thyroid gland, parathyroid glands, adrenal glands, pancreas, ovaries (in females) and testicles (in men).

The cause of pituitary tumors remains unknown. Pituitary tumors are almost always noncancerous (benign), which means they don't spread to other parts of your body, but they can increase in size. Because they grow in such limited space, they can compress and damage the normal pituitary tissue, interfering with hormone production. A tumor can also compress an optic nerve — the nerve that transmits visual information from your eye to your brain — slowly causing loss of vision.

Although pituitary tumors can occur at any age, they're most likely to occur in older people. People with a family history of multiple endocrine neoplasia type 1 (MEN 1) have an increased risk of pituitary tumors. In MEN 1, multiple tumors occur in various glands of the endocrine system.

If you develop signs and symptoms that may be associated with a pituitary tumor, see your doctor to determine the exact cause. Pituitary tumors often can be treated effectively to return your hormone levels to normal and alleviate your signs and symptoms.

Blood tests detect the overproduction or deficiency of hormones as a result of a pituitary tumor. Other tests can determine the type of tumor, if it has grown and how much. Additional tests your doctor may recommend include:

• Brain imaging. A computerized tomography (CT) or magnetic resonance imaging (MRI) scan of your brain can detect a pituitary tumor.
• Vision testing. Such tests can determine if growth of a pituitary tumor has impaired your sight or peripheral vision.
• Bone imaging. In children, an X-ray of the hand and wrist can measure whether bone growth is normal.

In addition, your doctor may refer you for more extensive testing to a doctor who specializes in treating disorders of the endocrine system (endocrinologist).

Pituitary tumors usually don't grow or spread extensively. However, they can adversely affect your health. If a tumor grows larger than 1 inch in diameter, complications may occur, such as:

• Vision loss. A pituitary tumor can put pressure on the optic nerves, which are close to the pituitary gland, and cause loss of vision.
• Decreased hormone production. A pituitary tumor can press on surrounding pituitary tissue and cause a decrease in pituitary hormone production (hypopituitarism).
• Increased hormone production. A pituitary tumor can cause excess production of normal pituitary hormones, resulting in associated signs and symptoms.

Treatment for a pituitary tumor depends on the type of tumor, its size and how far it has grown into your brain. Your age and overall health also are factors. Because pituitary tumors can cause serious problems by putting pressure on your brain, treatment often is necessary. Early detection of pituitary tumors is key to successful treatment.

Treatment often involves a team of medical experts, including:

• A brain surgeon (neurosurgeon)
• An ear, nose and throat surgeon (otorhinolaryngologist)
• A doctor who specializes in disorders of the endocrine glands (endocrinologist)
• A doctor who specializes in interpreting medical images (radiologist)
• A doctor who specializes in radiation therapy (radiation oncologist)
• A doctor who specializes in the nervous system (neurologist)

Doctors generally use surgery, radiation therapy and medications, either alone or in combination, to treat a pituitary tumor and return hormone production to normal levels.

Surgery
The most common treatment for pituitary tumors is surgery. Surgical removal of a pituitary tumor usually is necessary if the tumor is pressing on an optic nerve, which can cause loss of vision. The success of surgery depends on the tumor type, its location, its size, and whether the tumor has invaded surrounding tissues. The two main surgical techniques for treating pituitary tumors are:

• Transsphenoidal hypophysectomy. With this approach, a doctor usually can reach and remove the tumor through your nose and sinuses without an external incision. No other part of your brain is affected, and there's no visible scar. However, very large tumors may be difficult to remove with this procedure, especially if a tumor has invaded nearby nerves or brain tissue.
• Transcranial hypophysectomy. During this procedure, the tumor is removed through the upper part of your skull by way of an incision in your scalp. It's easier to reach large or more complicated tumors using this procedure.

Radiation therapy
Radiation therapy uses high-energy X-rays to destroy tumors. It can be used after surgery or alone as primary treatment if surgery isn't an option. Radiation therapy can be beneficial if a tumor persists or returns after surgery and causes signs and symptoms that medications don't relieve. Methods of radiation therapy include:

• External beam radiation. This form of radiation therapy delivers radiation in small increments over a period of time. A series of treatments, usually five times a week over a four- to six-week period, are performed on an outpatient basis. While this therapy is often effective, it may take years to fully control the tumor growth and hormone production. Radiation therapy may also damage remaining normal pituitary cells and normal brain tissue, particularly near the pituitary gland.

• Gamma-knife radiosurgery. This type of radiation therapy focuses radiation beams precisely on the tumor without an incision. Radiation beams that are the exact size and shape of the tumor are delivered into the tumor with the aid of special brain-imaging techniques. With gamma-knife radiosurgery, a minimal amount of radiation comes in contact with healthy tissue surrounding the tumor, decreasing the risk of damage to normal tissue.

  The benefits of gamma-knife radiosurgery, like those of external beam radiation, often aren't immediate and may take months or years to be fully effective. Gamma-knife radiosurgery is a relatively new treatment for pituitary tumors, but early results have been encouraging. However, doctors can't use this therapy if the tumor is very close to an optic nerve or other sensitive structures.

Medications
Treatment with medications (drug therapy) may help to block excess hormone secretion and sometimes shrink certain types of pituitary tumors:

• Prolactin-producing tumors (prolactinomas). The drugs bromocriptine (Parlodel) and cabergoline (Dostinex) can treat these types of tumors by decreasing prolactin secretion and often reducing the size of the tumor. These drugs are often so effective in treating these types of tumors that surgery isn't necessary.
• Growth hormone-producing tumors. Two classes of drugs are available for these types of pituitary tumors. Drugs known as somatostatin analogs (Sandostatin, others) cause a decrease in growth hormone production and may decrease the size of the tumor. Pegvisomant (Somavert) blocks the effect of excess growth hormone on the body. These medications are especially useful if surgery has been unsuccessful in normalizing growth hormone production.

If a pituitary tumor has resulted in decreased hormone production, or if removal of a pituitary tumor has lowered hormone production, you may need to take replacement hormones to maintain normal hormone levels.

Watchful waiting
In watchful waiting — also known as observation, expectant therapy or deferred therapy — you may need regular follow-up tests to monitor for evidence of progression of your pituitary tumor. Watchful waiting involves no active medical treatment. Medications, radiation therapy and surgery aren't used. Watchful waiting may be an option if your tumor isn't causing any signs or symptoms.

Watchful waiting may be particularly appropriate if you're older, in poor health or both. Many people with pituitary tumors function normally without treatment and without the tumor causing other problems. If you're younger, watchful waiting can also be an option as long as you know the facts and accept the possibility of your tumor changing or growing during the observation period, possibly requiring medical treatment. You and your doctor can weigh the risk of symptoms developing versus treatment intervention.

It's natural for you and your family to have many questions throughout the diagnosis and treatment of a pituitary tumor. The process can be overwhelming — and frightening. That's why it might help to write down your questions and bring them with you to your appointments. As your doctor answers your questions, take notes or ask a family member to accompany you and take notes. The more you and your family know and understand about each aspect of your care, the better.

You might also find it helpful to share your feelings with others in similar situations. Check to see if support groups for people with pituitary tumors and their families are available in your area. Hospitals often sponsor these groups. Your doctors and nurses also may be able to make recommendations on where to find the emotional support you might need.