Medically reviewed by Drugs.com. Last updated on Mar 31, 2021.
Pituitary tumors are abnormal growths that develop in your pituitary gland. Some pituitary tumors result in too much of the hormones that regulate important functions of your body. Some pituitary tumors can cause your pituitary gland to produce lower levels of hormones.
Most pituitary tumors are noncancerous (benign) growths (adenomas). Adenomas remain in your pituitary gland or surrounding tissues and don't spread to other parts of your body.
There are various options for treating pituitary tumors, including removing the tumor, controlling its growth and managing your hormone levels with medications. Your doctor may recommend observation — or a ''wait and see'' approach.
A pituitary tumor is a tumor that forms in the pituitary gland near the brain that can cause changes in hormone levels in the body. This illustration shows a smaller tumor (microadenoma).
Not all pituitary tumors cause symptoms. Sometimes they are identified incidentally on an imaging test such as an MRI or CT performed for some other reason. Pituitary tumors that make hormones (functioning) can cause a variety of signs and symptoms depending on the hormone they produce. The signs and symptoms of pituitary tumors that don't make hormones (nonfunctioning) are related to their growth and the pressure they put on other structures.
Large pituitary tumors — those measuring about 1 centimeter (slightly less than a half-inch) or larger — are known as macroadenomas. Smaller tumors are called microadenomas. Because of the size of macroadenomas, they can put pressure on the normal pituitary gland and nearby structures.
Signs and symptoms related to tumor pressure
Signs and symptoms of pressure from a pituitary tumor may include:
- Vision loss, particularly loss of peripheral vision
Symptoms related to hormone level changes
Large tumors could cause hormonal deficiencies. Signs and symptoms include:
- Nausea and vomiting
- Feeling cold
- Less frequent or no menstrual periods
- Sexual dysfunction
- Increased amount of urine
- Unintended weight loss or gain
Functioning pituitary tumors cause an overproduction of hormones. Different types of functioning tumors in your pituitary gland cause specific signs and symptoms and sometimes a combination of them.
Adrenocorticotropic hormone-secreting (ACTH) tumors
ACTH tumors produce the hormone adrenocorticotropin, which stimulates your adrenal glands to make the hormone cortisol. Cushing syndrome results from your adrenal glands producing too much cortisol. Possible signs and symptoms of Cushing syndrome include:
- Fat accumulation around your midsection and upper back
- Exaggerated facial roundness
- Thinning of the arms and legs with muscle weakness
- High blood pressure
- High blood sugar
- Bone weakening
- Stretch marks
- Anxiety, irritability or depression
Growth hormone-secreting tumors
These tumors produce excess growth hormone (acromegaly), which can cause:
- Coarsened facial features
- Enlarged hands and feet
- Excess sweating
- High blood sugar
- Heart problems
- Joint pain
- Misaligned teeth
- Increased body hair
Children and adolescents might grow too fast or too tall.
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 affects men and women differently.
In women, prolactinoma might cause:
- Irregular menstrual periods
- Lack of menstrual periods
- Milky discharge from the breasts
In men, a prolactin-producing tumor may cause male hypogonadism. Signs and symptoms can include:
- Erectile dysfunction
- Lowered sperm count
- Loss of sex drive
- Breast growth
Thyroid-stimulating hormone-secreting 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:
- Weight loss
- Rapid or irregular heartbeat
- Nervousness or irritability
- Frequent bowel movements
- Excessive sweating
When to see a doctor
If you develop signs and symptoms that might be associated with a pituitary tumor, see your doctor. Pituitary tumors often can be treated to return your hormone levels to normal and alleviate your signs and symptoms.
If you know that multiple endocrine neoplasia, type 1 (MEN 1) runs in your family, talk to your doctor about periodic tests that may help detect a pituitary tumor early.
The cause of uncontrolled cell growth in the pituitary gland, which creates a tumor, remains unknown.
The pituitary gland is a small, bean-shaped gland situated at the base of your brain, somewhat behind your nose and between your ears. Despite its small size, the gland influences nearly every part of your body. The hormones it produces help regulate important functions, such as growth, blood pressure and reproduction.
A small percentage of pituitary tumor cases run in families, but most have no apparent hereditary factor. Still, scientists suspect that genetic alterations play an important role in how pituitary tumors develop.
The pituitary gland and the hypothalamus are located within the brain and control hormone production.
People with a family history of certain hereditary conditions, such as 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. Genetic testing is available for this disorder.
Pituitary tumors usually don't grow or spread extensively. However, they can affect your health, possibly causing:
- Vision loss. A pituitary tumor can put pressure on the optic nerves.
- Permanent hormone deficiency. The presence of a pituitary tumor or the removal of one may permanently alter your hormone supply, which may need to be replaced with hormone medications.
A rare but potentially serious complication of a pituitary tumor is pituitary apoplexy, when sudden bleeding into the tumor occurs. It feels like the most severe headache you've ever had. Pituitary apoplexy requires emergency treatment, usually with corticosteroids and possibly surgery.
Pituitary tumors often go undiagnosed because their symptoms resemble those of other conditions. And some pituitary tumors are found because of medical tests for other conditions.
To diagnose a pituitary tumor, your doctor will likely take a detailed history and perform a physical exam. He or she might order:
- Blood and urine tests. These tests can determine whether you have an overproduction or deficiency of hormones.
- Brain imaging. A CT scan or MRI scan of your brain can help your doctor judge the location and size of a pituitary tumor.
- Vision testing.This can determine if a pituitary tumor has impaired your sight or peripheral vision.
In addition, your doctor might refer you to an endocrinologist for more-extensive testing.
Many pituitary tumors don't require treatment. Treatment for those that do 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.
Treatment involves a team of medical experts, possibly including a brain surgeon (neurosurgeon), endocrine system specialist (endocrinologist) and a radiation oncologist. 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.
Surgical removal of a pituitary tumor usually is necessary if the tumor is pressing on the optic nerves or if the tumor is overproducing certain hormones. 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:
- Endoscopic transnasal transsphenoidal approach. This usually enables your doctor to 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. Large tumors may be difficult to remove this way, especially if a tumor has invaded nearby nerves or brain tissue.
- Transcranial approach (craniotomy). The tumor is removed through the upper part of your skull via an incision in your scalp. It's easier to reach large or more-complicated tumors using this procedure.
Radiation therapy uses high-energy sources of radiation to destroy tumors. It can be used after surgery or alone 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:
- Stereotactic radiosurgery. Often delivered as a single high dose, this focuses radiation beams on the tumor without an incision. It delivers radiation beams the size and shape of the tumor into the tumor with the aid of special brain-imaging techniques. Minimal radiation comes in contact with healthy tissue surrounding the tumor, decreasing the risk of damage to normal tissue.
- External beam radiation. This delivers radiation in small increments over time. A series of treatments, usually five times a week over a four- to six-week period, is 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.
- Intensity modulated radiation therapy (IMRT). This type of radiation therapy uses a computer that allows the doctor to shape the beams and surround the tumor from many different angles. The strength of the beams can also be limited, which means surrounding tissues will receive less radiation.
- Proton beam therapy. Another radiation option, this type uses positively charged ions (protons) rather than X-rays. Unlike X-rays, proton beams stop after releasing their energy within their target. The beams can be finely controlled and can be used on tumors with less risk to healthy tissues. This type of therapy requires special equipment and isn't widely available.
The benefits and complications of these forms of radiation therapy often aren't immediate and may take months or years to be fully effective. A radiation oncologist will evaluate your condition and discuss the pros and cons of each option with you.
Treatment with medications may help to block excess hormone secretion and sometimes shrink certain types of pituitary tumors:
- Prolactin-secreting tumors (prolactinomas). The drugs cabergoline and bromocriptine (Parlodel, Cycloset) decrease prolactin secretion and often reduce tumor size. Possible side effects include drowsiness, dizziness, nausea, nasal stuffiness, vomiting, diarrhea or constipation, confusion, and depression. Some people develop compulsive behaviors, such as gambling, while taking these medications.
ACTH-producing tumors (Cushing syndrome). Medications to control excessive production of cortisol at the adrenal gland include ketoconazole, mitotane (Lysodren) and metyrapone (Metopirone). Osilodrostat (Isturisa) also decreases cortisol production. Potential adverse effects include a heart conduction abnormality that can lead to serious heartbeat irregularity. Mifepristone (Korlym, Mifeprex) is approved for people with Cushing syndrome who have type 2 diabetes or glucose intolerance. Mifepristone does not decrease cortisol production, but it blocks the effects of cortisol on your tissues. Side effects may include fatigue, nausea, vomiting, headaches, muscle aches, high blood pressure, low potassium and swelling.
Pasireotide (Signifor) works by decreasing ACTH production from a pituitary tumor. This medication is given as an injection twice daily. It is recommended if pituitary surgery is unsuccessful or cannot be done. Side effects are fairly common, and may include diarrhea, nausea, high blood sugar, headache, abdominal pain and fatigue.
Growth hormone-secreting tumors. Two types of drugs are available for these types of pituitary tumors and are especially useful if surgery has been unsuccessful in normalizing growth hormone production. One type of drugs known as somatostatin analogs, which includes drugs such as octreotide (Sandostatin, Sandostatin LAR Depot) and lanreotide (Somatuline Depot), causes a decrease in growth hormone production and may shrink the tumor. These are given by injections, usually every four weeks. An oral preparation of octreotide (Mycapssa) is now available and has similar efficacy and side effects as the injectable preparation.
These drugs can cause side effects such as nausea, vomiting, diarrhea, stomach pain, dizziness, headache and pain at the site of injection. Many of these side effects improve or even go away with time. They can also cause gallstones and may worsen diabetes mellitus.
The second type of drugs, pegvisomant (Somavert), blocks the effect of excess growth hormone on the body. This drug, given by daily injections, may cause liver damage in some people.
Replacement of pituitary hormones
If a pituitary tumor or surgery to remove it decreases hormone production, you'll likely need to take replacement hormones to maintain normal hormone levels. Some people who have radiation treatment also need pituitary hormone replacement.
In watchful waiting — also known as observation, expectant therapy or deferred therapy — you might need regular follow-up tests to determine if your tumor grows. This might be an option if your tumor isn't causing signs or symptoms.
Many people with pituitary tumors function normally without treatment if the tumor isn't causing other problems. If you're younger, watchful waiting can be an option as long as you accept the possibility of your tumor changing or growing during the observation period, possibly requiring treatment. You and your doctor can weigh the risk of symptoms developing versus treatment.
During transsphenoidal endoscopic surgery, a surgeon accesses the pituitary tumor by inserting a tiny, specialized surgical instrument into the nostril and alongside the nasal septum.
Coping and support
It's natural for you and your family to have questions throughout the diagnosis and treatment of a pituitary tumor. The process can be overwhelming — and frightening. That's why it's important to learn as much as you can about your condition. 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 medical team also may be able to help you find the emotional support you might need.
Preparing for an appointment
You're likely to start by seeing your primary care provider. If your doctor finds evidence of a pituitary tumor, he or she might recommend you see several specialists, such as a brain surgeon (neurosurgeon) or a doctor who specializes in disorders of the endocrine system (endocrinologist).
Here's some information to help you prepare for your appointment.
What you can do
When you make the appointment, ask if there's anything you need to do in advance, such as fasting before having a specific test. Make a list of:
- Your symptoms, including any that may seem unrelated to the reason for your appointment
- Key personal information, including major stresses or recent life changes and family medical history
- Medications, vitamins or supplements you take, including doses
- Questions to ask your doctor
Take a family member or friend along, if possible, to help you retain the information you receive.
For a pituitary tumor, questions to ask your doctor include:
- What is likely causing my symptoms or condition?
- What are other possible causes?
- What specialists should I see?
- What tests do I need?
- What is the best course of action?
- What are alternatives to the primary approach you're suggesting?
- I have these other health conditions. How can I manage them together?
- Are there restrictions I need to follow?
- Are there brochures or other printed materials I can have? What websites do you recommend?
Don't hesitate to ask other questions.
What to expect from your doctor
Questions your doctor is likely to ask include:
- When did your symptoms begin?
- Have they been continuous or occasional?
- How severe are your symptoms?
- What, if anything, seems to improve your symptoms?
- What, if anything, appears to worsen your symptoms?
- Have you had previous imaging of your head for any reason in the past?