What’s a pituitary tumor? 4 things you need to know

By Jessica Saenz

The pituitary gland is a pea-sized organ with big responsibilities. The gland, which sits at the base of your brain, secretes hormones that control vital body functions or instructs other organs to release hormones. When tumors develop in the pituitary gland, they can sometimes disrupt the gland's work, even when tumors are not cancerous.

Pituitary tumors, also called pituitary adenomas, can develop at any age. Jamie Van Gompel, M.D., a Mayo Clinic neurosurgeon, says that though they are rarely cancerous, they can cause problems.

Here are four things you need to know about pituitary tumors and how they can affect you:

1. Pituitary tumors are common but rarely cancerous.

Each year, more than 10,000 pituitary tumors are diagnosed in the U.S., but the actual number of people with pituitary tumors may be higher because they don't always cause symptoms, according to the American Cancer Society. "They're very common," says Dr. Van Gompel. "Out of all the brain-related tumors we see at Mayo Clinic, about 10% are pituitary tumors."

According to the National Institutes of Health, less than 0.1% of pituitary tumors are cancerous. Although he sees many patients with pituitary tumors every year, Dr. Van Gompel says only one or two have a cancerous tumor or pituitary carcinoma. These tumors can be treated with surgery, radiation, chemotherapy, and drug therapies.

2. Pituitary tumors are categorized in two ways.

Some pituitary tumors don't produce hormones and are called non-functioning tumors. Those that do produce hormones are called functioning tumors. "Out of all pituitary tumors, about half of them aren't making any kind of substance," says Dr. Van Gompel. "They cause problems by putting pressure on things nearby like the optic nerve, causing vision loss. Or they'll take up enough room and disrupt the function of the pituitary gland."

Functioning tumors, which produce hormones, most often cause three distinct syndromes:

• Prolactinoma: The tumor produces too much of a hormone called prolactin. In females, this could mean irregular or no menstrual periods, or milky discharge from the breasts unrelated to pregnancy. In males, it could mean decreased body and facial hair, erectile dysfunction, or enlarged breasts.
• Cushing syndrome: The tumor tells the adrenal glands to make too much of a hormone called cortisol, which can result in physical symptoms like a fatty hump between the shoulders, weight gain around the belly, pink and purple stretch marks, high blood pressure, and sometimes Type 2 diabetes.
• Acromegaly: The tumor produces too much growth hormone. Symptoms may include enlarged hands, feet, and facial features in adults, joint pain and muscle weakness, and coarse, oily, thickened skin. Rarely, when it develops in children, it can cause gigantism. If left untreated, patients get diabetes and potentially heart failure from an enlarged heart. 

3. Pituitary tumors can be treated with medication but sometimes require surgery.

If a tumor is detected in your testing, it might not immediately require surgery or treatment. "We commonly watch small tumors that aren't causing problems," says Dr. Van Gompel. "Prolactin-secreting tumors can be treated with medication. In patients with acromegaly or Cushing's syndrome, we often take out the tumor to treat the disease."

If you need surgery to remove the tumor, Dr. Van Gompel says technology makes the procedure and recovery much easier. "Fortunately, the pituitary gland is in the back of the nose, and most surgeons use endoscopic surgery now," says Dr. Van Gompel. "The procedure is not very long. For most patients, it's usually about 60 to 90 minutes, and the recovery is quite easy."

With endoscopic surgery, you won't have an external incision, and Dr. Van Gompel says there may be additional benefits. "If you've previously had some obstruction like a deviated septum or some of the things that cause breathing issues, we have to fix that to get back there. I tell patients all the time, 'You might get a twofer with this one.'" he says.

4. Pituitary tumor recurrence is uncommon, and technology is improving treatment.

Tumor recurrence in non-functioning tumors that don't produce hormones is uncommon. "Even before modern-day techniques, as long as about 85% of the tumor was removed, the chance of needing another treatment over the next decade was only 10%," says Dr. Van Gompel. He adds that if tumor regrowth occurs, a single session of radiation treatment can often stop it without additional surgery.

If your tumor is large, or the hormones it produces are causing other complications and syndromes, you may need additional treatment after surgery. Dr. Van Gompel says artificial intelligence is helping the Mayo Clinic Brain Tumor Program determine the best course of treatment upfront. "We can now tabulate characteristics like your age, the size of your tumor, and hormone levels, and calculate the chance we can cure you and the potential treatment options," he says.

As better imaging helps health care professionals diagnose and treat more pituitary tumors, Dr. Van Gompel says treatments will continue to improve. "We'll continue to study outcomes and ensure they are as good, if not better, than last year," he says.

Learn more

Learn more about pituitary tumors and find a pituitary tumor clinical trial at Mayo Clinic.

Watch Dr. Van Gompel discuss pituitary tumors and treatment options in this "Mayo Clinic Q&A" podcast video: