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
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
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.