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.