Pituitary Tumor

A pituitary tumor is a tumor that forms in the pituitary gland. The pituitary gland is located at the base of the brain, just behind the back of the nasal cavity The pituitary gland makes hormones that affect many other glands and many functions in your body. Most pituitary tumors are not cancerous. They don’t spread to other parts of your body. It is relatively common for pituitary tumors to cause problems with too much or too little hormone production.

Pituitary tumors that make too many hormones will cause specific problems that depend on the type of hormone produced. Many large pituitary tumors will press against the nearby optic nerves. This can cause vision problems.

Most pituitary tumors don’t cause symptoms. So they are not diagnosed. Or they are found only during routine brain imaging or blood tests. About 1 in 4 people may have small pituitary tumors without knowing it.

Below are the main types of pituitary tumors.

Nonfunctional adenomas (null cell adenomas)

These tumors are the most common type. They don’t make extra hormones and often don’t cause any symptoms until the tumor reaches a certain size. When the tumor is big enough, it may cause headaches and vision problems. Large pituitary tumors can also put pressure on normal pituitary cells. This leads to symptoms caused by decreased hormone production.

Prolactin-producing tumors (prolactinomas)

These benign tumors are also common. They make too much prolactin. If you are a woman, high prolactin levels can make your menstrual period irregular, or even stop your period. These tumors can also cause you to make breastmilk, even if you are not pregnant or nursing. If you are a man, you may have erectile dysfunction or a lack of interest in sex. You may also have enlarged breasts, a low sperm count, or less body hair. In time, you may have headaches and vision problems.

ACTH-producing tumors

These tumors make too much ACTH (adrenocorticotropic hormone). This hormone stimulates the adrenal gland to make steroids that affect metabolism. These are called glucocorticoids. They reduce redness and swelling (inflammation) all over the body. They also slow down your immune system. Too much ACTH can cause Cushing disease. This disease causes fat buildup in your face, neck, back, belly (abdomen), and chest. Also your arms and legs tend to become thin. You may also have purple stretch marks and high blood pressure. These tumors can also weaken your bones.

Growth hormone-producing tumors

These tumors make too much growth hormone. In children, too much growth hormone stimulates the growth of almost all the bones in the body. When that occurs, the result is called gigantism. Gigantism can include increased height (over 7 feet), very quick growth, joint pain, and heavy sweating. In adults, too much growth hormone causes a condition called acromegaly. It may include:

• Extra growth in the skull, hands, and feet.
• Deepened voice.
• A change in the facial appearance because of extra growth in the facial bones.
• A wide spacing of teeth because of the growth of facial bones.
• Joint pain.
• Snoring or sleep apnea.
• Diabetes or impaired glucose tolerance.
• High blood pressure from enlargement of the heart muscle and fluid retention.

Experts don't know what causes these tumors. But a condition called multiple endocrine neoplasia type 1 (MEN1) may raise your risk. This condition is passed down through families.

Not all pituitary tumors cause symptoms. But those that do can cause different kinds of symptoms.

Pituitary tumors that make too many hormones (functional) cause symptoms linked to the hormone they produce.

Pituitary tumors that don’t make too many hormones (nonfunctional) can grow large (macroadenomas). They cause symptoms because they press on nearby nerves and other areas.

Large noncancerous and cancerous pituitary tumors may press on nerves or parts of the brain. This can cause the following symptoms:

• Double or blurred vision.
• Loss of side (peripheral) vision.
• Sudden loss of sight.
• Headaches.
• Dizziness.
• Numbness or pain in the face.
• Fainting.

These types of tumors may also press on and damage parts of the pituitary gland. This can reduce the amount of pituitary hormones. This may lead to symptoms such as:

• Upset stomach (nausea).
• Weakness.
• Unwanted weight loss or gain.
• Loss of menstrual periods.
• Men having problems keeping an erection (impotence).
• Less interest in sex.

Functional pituitary tumors can cause different symptoms, based on the excess hormone they make. 

Pituitary tumors that make growth hormone (GH)

Symptoms caused by having too much GH are different in children than in adults. For children, symptoms include:

• Rapid growth.
• Pain in joints.
• Too much sweating.
• Being abnormally tall (gigantism).
• Over time, adults with tumors that cause high GH levels may have the following symptoms:
• Increase in hat, shoe, or ring size caused by growth of head, hands, or feet.
• Deeper voice.
• Change in facial structure.
• Joint pain.
• Too much sweating.
• Headache.
• Heart disease.
• Diabetes.
• Kidney stones.
• High blood pressure.

Pituitary tumors that make ACTH (corticotropin)

Pituitary tumors that make the hormone ACTH cause the adrenal glands to make too many steroid hormones. This may lead to the following symptoms:

• Weight gain, often in the belly.
• Purple stretch marks on the belly.
• A hump of fat on the back of the neck.
• Abnormal growth of body hair.
• A round, swollen face.
• Less interest in sex.
• Weak, brittle bones (osteoporosis).
• Acne.
• High blood pressure.
• High blood sugar levels.
• Irregular or absent menstrual periods in women.

Other more rare kinds of pituitary tumors cause other symptoms. If you have any abnormal symptoms, see your healthcare provider.

Many of these symptoms may be caused by other health problems. But it is important to see your healthcare provider if you have these symptoms. Only a healthcare provider can order appropriate labs and imaging and tell if you have a pituitary tumor.

Your healthcare provider will ask about your health history and do a physical exam. You may also need one of these tests:

• Blood and urine tests. These tests will check hormone levels in your blood and urine.
• CT scan. This test uses X-rays and a computer to make detailed images of your body.
• MRI. This test uses large magnets, radio waves, and a computer to make detailed images of organs and structures in your body.
• Biopsy. During this test, the provider removes a tissue sample with a needle or during surgery. It is then checked under a microscope. A biopsy can tell if cancer or other abnormal cells are present.

Treatment will depend on your symptoms, age, and general health. It will also depend on how severe the condition is.

Treatment may include:

• Surgery to remove the tumor. Surgery is often a better option for smaller tumors.
• External radiation (external beam therapy). This treatment sends high levels of radiation right to the tumor cells. Special shields may be used to protect the tissue around the treatment area. These treatments are painless and often last a few minutes.
• Radiosurgery (stereotactic radiosurgery) or gamma knife treatment. This is often one high dose of radiation sent right into the tumor tissue. It causes less damage to nearby tissues. It is not actually surgery. But like surgery, it is a one-session treatment that removes the tumor.
• Medicine. Different types of medicine may be used to control how much growth hormone, prolactin, or other hormone is made by the tumor.

Known risk factors for pituitary tumors are linked to inherited genetic syndromes. These are abnormal changes (mutations) in certain genes that are passed down from parent to child. These hereditary risks include:

• MEN1 (multiple endocrine neoplasia, type 1). This condition is caused by changes in the gene MEN1. Having MEN1 syndrome raises your risk for pituitary tumors and some other tumors. If a parent has changes to the MEN1 gene, the child has a 50% chance of getting MEN1.
• MEN4. People with this rare syndrome have a higher risk for pituitary tumors and some other tumors. MEN4 is caused by changes in the gene CDKN1B that are passed down from a parent.

Other rare inherited and non-inherited genetic problems can also raise the risk of pituitary tumors. Changes in the gene AIP can also be a risk factor. These changes can be passed down from a parent. Or they can occur at some point during your life.

In rare cases, pituitary tumors seem to run in some families without a known genetic syndrome.

No standard screening methods are used to find pituitary tumors in people who are not known to be at increased risk. If you have an inherited condition such as MEN1 syndrome, talk about screening with your healthcare provider. If any of your family members have MEN1 syndrome, you may have regular blood testing to look for abnormal pituitary hormone levels. These blood tests raise the chances of finding a tumor early so it can be treated.