DEAR MAYO CLINIC: My doctor says I have a pituitary tumor. What is the pituitary gland, where is it located, and what does this diagnosis mean?
ANSWER: The pituitary gland is a small, pea-sized gland located behind the nose at the base of the brain, near the nerves involved in vision. It produces hormones and sends signals that help regulate growth, metabolism, reproduction and the body's response to stress.
Most pituitary tumors are noncancerous, and some don't require treatment. What the diagnosis means for you depends primarily on the tumor's size and location, whether it extends into the cavernous sinus — a nearby area that contains the carotid arteries — and how it affects hormone production.
Most pituitary tumors are called pituitary adenomas. An adenoma is a noncancerous tumor that develops from the tissue of the gland. Most pituitary adenomas remain in or near the pituitary gland and don't spread to other parts of the body.
How can a pituitary tumor affect your health?
A pituitary tumor can affect your health in two main ways: by changing hormone levels or by growing large enough to press on the actual pituitary gland or nearby structures. Because the pituitary gland sits close to the optic nerves, a larger tumor can affect vision.
Pituitary tumors and adenomas generally fall into two broad groups:
- Functioning tumors make hormones, which can cause hormone levels in the body to become too high. Symptoms depend on which hormone is involved.
- Nonfunctioning tumors don't make excess hormones that affect your body. Instead, they can cause problems if they grow large enough to press on the pituitary gland, reducing its normal hormone production — including hormones involved in puberty and pregnancy — or on nearby structures such as the optic nerves.
What symptoms can pituitary tumors cause?
Some pituitary tumors cause no symptoms and are found during imaging performed for another reason. When symptoms do occur, a larger tumor or reduced pituitary function may cause:
- Headache.
- Vision changes, particularly loss of peripheral or side vision.
- Tiredness, weakness or low energy.
- Changes in sexual function or interest in sex.
- Changes in menstrual cycles.
Hormone-producing tumors can cause more specific symptoms depending on which hormone is involved:
- Prolactin-producing tumors can cause milky breast discharge unrelated to pregnancy or nursing, menstrual changes, fertility problems, impotence, or sexual difficulties.
- Tumors that cause Cushing disease lead the body to make too much cortisol. Signs can include weight gain, high blood pressure and high blood sugar.
- Growth hormone-producing tumors can cause acromegaly in adults. Signs may include enlargement of the hands, feet or facial features, increased sweating, and joint pain.
These symptoms can have many causes and don't necessarily mean someone has a pituitary tumor. However, new, persistent or worsening symptoms, particularly vision changes or signs of a hormone imbalance, should be discussed with a healthcare professional.
When is a pituitary tumor an emergency?
Rarely, sudden bleeding into a pituitary tumor can cause a serious condition called pituitary apoplexy. An abrupt, extremely severe headache accompanied by vision problems, vomiting or confusion requires immediate medical care.
Following a pituitary tumor diagnosis, evaluation may include:
- Blood tests to determine whether hormone levels are too high or too low.
- An MRI to show the tumor's size and location, including how close it is to the nerves involved in vision.
- Vision testing, particularly when the tumor is near the optic nerves.
How are pituitary tumors treated?
Treatment depends on the tumor's type, size and location; the symptoms it is causing; and its effects on hormone levels. Small tumors that aren't causing problems may be monitored over time. Some tumors can be treated with medication. For example, prolactin-producing tumors often respond to medicines that lower prolactin levels and may shrink the tumor.
Surgery may be recommended when a tumor affects vision, interferes with pituitary gland function or produces certain excess hormones. Radiation therapy may be used in selected situations.
The crucial point is that a pituitary tumor diagnosis can mean different things for different people. Understanding the tumor's size, location and effect on hormone production can help you and your healthcare team determine whether treatment is needed and which approach is most appropriate.
Jamie Van Gompel, M.D., Neurosurgery, Mayo Clinic, Rochester, Minnesota