Signs and symptoms of pituitary tumors

For all adenomas

These tumors may cause problems because of the hormones they release. If no excess hormone is being produced, these tumors often become large before they are noticed. Large tumors can affect nearby tissues, leading to headaches and visual problems.

Typically, a functional adenoma makes too much of a single pituitary hormone -- without making too much of the other hormones. As the tumor gets larger, it puts pressure on the normal pituitary tissue. This can lead to a loss of normal pituitary hormone production, and low levels of some normal body hormones such as cortisone, thyroid hormone, and sex hormones.

Non-functional adenomas that cause no symptoms are sometimes found because of an MRI taken for other reasons. These "incidentalomas." are being discovered more often as more MRI and CT scans of the brain are done. These may be the most common pituitary tumors. They probably do not need treatment.

Macroadenomas and pituitary carcinomas

Pituitary carcinomas are rare cancers usually found after they cause visual problems or other neurologic symptoms. Benign macroadenomas (tumors larger than 1 cm), whether functional or not, can also lead to neurologic symptoms that may include:

• paralysis of eye movements causing double or blurred vision
• loss of peripheral vision
• sudden blindness
• facial numbness or pain
• headache
• dizziness
• loss of consciousness

Vision problems occur when the tumor "pinches" the nerves that extend between the eyes and the brain. Sudden loss of vision, loss of consciousness, and even death can result from sudden bleeding into the tumor.

Macroadenomas and pituitary carcinomas can destroy normal pituitary tissue, creating a shortage of one or more pituitary hormones. Depending on which hormones are affected, the symptoms might include:

• nausea
• weakness
• unexplained weight loss or weight gain
• amenorrhea (no menstrual periods)
• erectile dysfunction in men, also known as impotence (difficulty having erections)
• decreased interest in sex, mainly in men

Diabetes insipidis: This syndrome can occur with any macroadenoma or with pituitary carcinoma. Diabetes insipidus also can occur as a complication of any pituitary tumor treatment. It should not be confused with diabetes mellitus (high sugar levels in the blood and urine).

Diabetes insipidus results when the pituitary makes too little vasopressin (also called anti-diuretic hormone, or ADH). ADH is what tells the kidneys to concentrate the urine. Not having enough of this hormone causes loss of water with frequent urination. This can be severe. As a result, the person becomes very thirsty as the body tries to keep up with the loss of water. If severe and untreated, this problem causes blood mineral abnormalities, which can lead to coma and even death. Fortunately, this condition is easily treated with a drug that replaces the vasopressin.

Growth hormone-secreting adenomas

The major symptoms of these are directly related to growth hormone overproduction. The effects of excessive growth hormone levels on children and adults are quite different.

In children, high growth hormone levels can stimulate the growth of nearly all bones in the body. The medical term for this condition is gigantism. Its features typically include:

• being very tall (sometimes over 7 feet)
• very rapid growth
• joint pains
• increased sweating

The long bones of adults (especially in the arms and legs) cannot grow further, even when growth hormone levels are very high. But bones of the hands, feet, skull, face, and jaws can grow throughout life. This is why adults with growth hormone-secreting adenomas do not grow taller and develop gigantism. Instead, they develop a different condition called acromegaly. The signs and symptoms of acromegaly are:

• growth of the skull, hands, and feet leading to increase in hat, shoe, glove, and ring size
• deepening of the voice
• change in the appearance of the face (due to growth of facial bones)
• wider spacing of the teeth (due to jawbone growth)
• joint pain
• increased sweating
• high blood sugar or even diabetes mellitus
• kidney stones
• heart disease
• headache
• thickening of tongue and roof of mouth, leading to sleep disturbances, including snoring and sleep apnea
• thickened skin
• increased growth of body hair

These changes can occur quite slowly, and often people don’t recognize how they’ve changed until they look at an old picture of themselves (or try to remove an old wedding band).

Corticotropin (ACTH)-secreting adenomas

Excessively high ACTH levels stimulate the adrenal glands to produce several steroid hormones. Oversupply of these steroid hormones causes several symptoms that doctors group together as Cushing's syndrome. When this originates from the high ACTH production from the pituitary it is termed Cushing's disease. In adults, these symptoms include:

• unexplained weight gain (mostly in the chest and abdomen)
• purple stretch marks on the abdomen
• new or increased hair growth (on the face, chest, and/or abdomen)
• swelling of the face
• fat deposits at the point where the back of the neck joins the spine
• moodiness or depression
• easy bruising
• high blood sugar or even diabetes mellitus
• hypertension (high blood pressure)
• irregular or absent menstrual periods
• weakening of the bones, which can lead to osteoporosis or even fractures

Most of the adult symptoms can also occur in children. Children with Cushing's disease may stop growing and start having problems in school performance. These changes occur much faster than acromegaly, so they are more easily recognized.

Prolactin-producing adenomas (prolactinomas)

Prolactinomas are most common in young women and older men. In adult women before the menopause, high prolactin levels cause menstrual periods to stop. High prolactin can also cause abnormal breast milk production, called galactorrhea. In men, impotence (not being able to have an erection) or loss of interest in sex may be the first symptom. If the tumor continues to grow, then headaches and vision problems can occur. In women who do not have periods (such as children before puberty and older women after menopause), prolactinomas may not be noticed until they cause these symptoms.

Thyrotropin (TSH)-secreting adenomas

When the tumor makes too much thyroid-stimulating hormone (TSH), it causes the thyroid gland to make too much thyroid hormone. Patients usually have symptoms of hyperthyroidism (overactive thyroid), such as:

• a rapid heartbeat
• tremors (shaking)
• weight loss
• an increased appetite
• feeling warm or hot
• difficulty falling asleep
• anxiousness
• frequent bowel movements
• a lump (enlarged thyroid) in the front of the neck

Gonadotropin-secreting adenomas

These adenomas make luteinizing hormone (LH) and/or follicle-stimulating hormone (FSH). They are not very common. Their overproduction of LH and/or FSH may cause irregular menstrual periods in women. Before these adenomas are detected, they may become large enough to cause headaches and problems with vision.

Medical history and physical exam

The first step is for the doctor to take a complete medical history to check for risk factors and symptoms. Your doctor will ask about your family history to see if you may have inherited the gene for multiple endocrine neoplasia, type I (MEN1). The doctor will want to know if anyone in your family has had a pituitary gland tumor, an overactive parathyroid gland (hyperparathyroidism), or adrenal gland tumors. They may also ask about problems with kidney stones, stomach ulcers, or low blood sugar (hypoglycemia), all of which can be signs of MEN1. The physical exam and visual exam provide more information about signs of pituitary tumors and other health problems.

Biochemical testing for pituitary tumors

Your symptoms and physical exam results may lead your doctor to believe that you might have a pituitary tumor. If your doctor suspects you have a hormone-producing tumor, your hormone levels in blood and/or urine samples will be measured.

Growth hormone-secreting adenomas

A physical exam may alert the doctor to look for these tumors because the signs and symptoms are often very distinctive. The next step is to check for excessive growth hormone production. Levels of growth hormone and insulin-like growth factor-1 (IGF-1) will be measured in your blood samples, which are taken the morning after an overnight fast. When growth hormone levels are high, they cause the liver to make more IGF-1. Testing the IGF-1 level can be more helpful than checking the level of growth hormone. The IGF-1 level doesn't change much during the day, but the level of growth hormone can go up and down.

If both levels are very high, the diagnosis is clearly a pituitary tumor. If the levels are slightly increased, a glucose suppression test is done. You will be asked to drink a sugary liquid, and the levels of growth hormone, IGF-1, and blood sugar will be measured at intervals afterward. The normal response to suddenly taking in so much sugar is a drop in growth hormone levels. If the growth hormone levels remain high, a pituitary adenoma is probably the cause.

Corticotropin (ACTH)-secreting adenomas

Most of the signs and symptoms of ACTH-secreting tumors come from having too much cortisol (an adrenal steroid hormone). Quite a few diseases can cause the body to make too much cortisol. Patients with symptoms suggesting this condition need tests to determine if a pituitary tumor is the cause.

These tests may include measuring levels of cortisol and ACTH in blood samples taken at different times of the day. The patient may be asked to collect all the urine that they produce over a 24-hour period, which is then tested to measure daily production of cortisol and other steroid hormones. Blood ACTH levels may be checked again after taking a dose of a powerful, cortisone-like drug called dexamethasone. These tests help to distinguish patients with ACTH-secreting tumors from patients with other diseases, such as adrenal gland tumors, that may cause similar symptoms.

Prolactin-secreting adenomas (prolactinomas)

Blood prolactin levels can be measured to check for a prolactinoma.

Gonadotropin-secreting adenomas

Luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels can be checked to see if a patient has a gonadotropin-secreting tumor.

Thyrotropin-secreting adenomas

Tests to measure blood levels of thyrotropin (TSH) and thyroid hormones can usually identify people with a thyrotropin-secreting adenoma.

Nonfunctional (null cell) adenomas

A pituitary adenoma is considered non-functional if it does not make too much pituitary hormone, so the pituitary hormone levels will not be increased. Sometimes, though, pituitary hormone blood levels may actually be lowered because the adenoma interferes with their production.

Testing for diabetes insipidus

Diabetes insipidus is caused by damage to the part of the pituitary that produces vasopressin. This condition can be caused by pituitary macroadenomas and carcinomas. It is sometimes caused by tumors arising from parts of the central nervous system next to the pituitary gland. Still, it occurs more commonly with metastatic cancer. It sometimes is a side effect of surgical treatment of pituitary tumors, or tumors next to the pituitary gland.

In many cases, this diagnosis is made by tests to measure sodium (salt) levels in the blood and osmolality (total salt concentration) of the blood and urine. If these tests are inconclusive, then a water deprivation study may be done. In this is a test, you are not allowed to drink fluids for several hours. The test is often done overnight. If your body is not making enough vasopressin, you will continue to make urine even though you are not taking in any fluid. You may also be given an injection of vasopressin to see if this corrects the problem.

Venous blood sampling

Corticotropin-secreting adenomas may be too small to be detected by magnetic resonance imaging (MRI) scans (see the next section). When the ACTH level is high, but the patient’s MRI scan is normal, a venous sampling study may be useful to find the tumor.

In this study, catheters (small tubes) are placed into the groin veins through a small nick in the skin and guided into the petrosal sinuses, which hold 2 small veins that drain the blood from each side of the pituitary gland. After an injection of corticotropin-releasing hormone (CRH), blood samples are taken from both sides and compared to see if the ACTH level is higher on one side than the other. The side with the higher ACTH level has the pituitary tumor.

Imaging tests

Computed tomography

The computed tomography (CT) scan is an x-ray procedure that creates detailed cross-sectional images of your body. Instead of taking one picture, like a standard x-ray, a CT scanner takes many pictures as the camera rotates around you. A computer then combines these pictures into an image of a slice of your body. The machine will take pictures of multiple slices of the part of your body that is being studied.

Before any pictures are taken, you may be asked to drink 1 to 2 pints of a liquid called "oral contrast." This helps outline the intestine so that certain areas are not mistaken for tumors. Oral contrast is rarely needed for CT scans of the brain.

You may also receive an IV (intravenous) line through which a different kind of contrast dye (IV contrast) is injected. This helps better outline tumors and other structures.

The injection can cause some flushing (redness and warm feeling that may last hours to days). A few people are allergic to the dye and get hives. Rarely, more serious reactions like trouble breathing and low blood pressure can occur. Medicine can be given to prevent and treat allergic reactions. Be sure to tell the doctor if you have ever had a reaction to any contrast material used for x-rays.

CT scans take longer than regular x-rays, and you will need to lie still on a table while they are being done. But the newest CT scans take only seconds to complete. Also, you might feel a bit confined by the ring-like equipment you’re in when the pictures are being taken.

The CT scan can find a pituitary adenoma if it is large enough. The MRI (see next section) is used much more often to look at the brain and pituitary.

Magnetic resonance imaging

Magnetic resonance imaging (MRI) scans use radio waves and strong magnets instead of x-rays. The energy from the radio waves is absorbed and then released in a pattern formed by the type of tissue and by certain diseases. A computer translates the pattern of radio waves given off by the tissues into a very detailed image of parts of the body. A contrast material, called gadolinium, is sometimes injected into a vein to improve the quality of the image.

MRI scans are particularly helpful in examining the brain and spinal cord. MRI is the best imaging test to identify pituitary tumors of all types. MRI can identify a macroadenoma of the pituitary gland, as well as most microadenomas. But the MRI may not be able to detect microadenomas that are smaller than 3 mm (about 1/8 inch). Sometimes the MRI scan will show a small abnormality in the pituitary that has nothing to do with the patient’s symptoms. Between 5% and 25% of healthy people have some minor abnormality of the pituitary gland that shows up on an MRI scan.

MRI scans can be uncomfortable. First, they take a long time -- often up to an hour. Also, you have to lie inside a tube, which is confining and can upset people with claustrophobia (a fear of enclosed spaces). The machine also makes a thumping noise, which can be disturbing. If you have problems with anxiety in tight spaces, talk to your doctor before the MRI. Sometimes, medicine can be given to help with the anxiety. It also may be possible to have the test done using an "open" MRI machine that is less confining and easier to tolerate. A trade-off is that open MRI machines may provide less detailed imaging of the pituitary tumor.

Testing of vision and visual fields

Because pituitary tumors can damage nerves leading to the eyes, your vision should be tested. The most common test is to measure how well a person can see. A more subtle test is to test the field of vision (or visual fields). At first, pituitary tumors only press on part of the optic nerves. This leads to part of a person’s vision being lost. This is usually the "peripheral vision," meaning things that you can see on one side or the other without actually looking directly at them. Eye doctors have special instruments that can test for this.

Examination of pituitary tissue specimens

In diagnosing tumors of most parts of the body, imaging tests and blood tests may strongly suggest a particular type of tumor. However, a biopsy (taking a sample of the tumor to examine under the microscope) is considered the only way to be certain of that diagnosis.

In many situations, doctors will not treat a tumor until a biopsy has been done. A pituitary tumor is one of the exceptions to this general rule. One reason is that the hormone tests for some types of adenomas are very accurate. The other reason is that some types of adenomas can be treated without surgery, using medicines or radiation therapy.

When pituitary tumors are removed by surgery, they are examined under a microscope to determine their exact type. Special stains may be used. These use special antibodies made the laboratory. They are attached to chemicals and color the areas of hormone production, which allows specific pituitary hormones to be seen.

Last Medical Review: 02/17/2009
Last Revised: 02/17/2009