A pituitary tumor is a tumor that forms in the pituitary gland. The pituitary gland is located at the base of the brain, just behind the back of the nasal cavity The pituitary gland makes hormones that affect many other glands and many functions in your body. Most pituitary tumors are not cancerous. They don’t spread to other parts of your body. It is relatively common for pituitary tumors to cause problems with too much or too little hormone production.
Pituitary tumors that make too many hormones will cause specific problems that depend on the type of hormone produced. Many large pituitary tumors will press against the nearby optic nerves. This can cause vision problems.
Most pituitary tumors don’t cause symptoms. So they are not diagnosed. Or they are found only during routine brain imaging or blood tests. About 1 in 4 people may have small pituitary tumors without knowing it.
Below are the main types of pituitary tumors.
Nonfunctional adenomas (null cell adenomas)
These tumors are the most common type. They don’t make extra hormones and often don’t cause any symptoms until the tumor reaches a certain size. When the tumor is big enough, it may cause headaches and vision problems. Large pituitary tumors can also put pressure on normal pituitary cells. This leads to symptoms caused by decreased hormone production.
Prolactin-producing tumors (prolactinomas)
These benign tumors are also common. They make too much prolactin. If you are a woman, high prolactin levels can make your menstrual period irregular, or even stop your period. These tumors can also cause you to make breastmilk, even if you are not pregnant or nursing. If you are a man, you may have erectile dysfunction or a lack of interest in sex. You may also have enlarged breasts, a low sperm count, or less body hair. In time, you may have headaches and vision problems.
These tumors make too much ACTH (adrenocorticotropic hormone). This hormone stimulates the adrenal gland to make steroids that affect metabolism. These are called glucocorticoids. They reduce redness and swelling (inflammation) all over the body. They also slow down your immune system. Too much ACTH can cause Cushing disease. This disease causes fat buildup in your face, neck, back, belly (abdomen), and chest. Also your arms and legs tend to become thin. You may also have purple stretch marks and high blood pressure. These tumors can also weaken your bones.
Growth hormone-producing tumors
These tumors make too much growth hormone. In children, too much growth hormone stimulates the growth of almost all the bones in the body. When that occurs, the result is called gigantism. Gigantism can include increased height (over 7 feet), very quick growth, joint pain, and heavy sweating. In adults, too much growth hormone causes a condition called acromegaly. It may include:
- Extra growth in the skull, hands, and feet.
- Deepened voice.
- A change in the facial appearance because of extra growth in the facial bones.
- A wide spacing of teeth because of the growth of facial bones.
- Joint pain.
- Snoring or sleep apnea.
- Diabetes or impaired glucose tolerance.
- High blood pressure from enlargement of the heart muscle and fluid retention.