Pituitary tumor

This page was reviewed under our medical and editorial policy by

Maurie Markman, MD, President, Medicine & Science

This page was updated on May 19, 2022.

A pituitary tumor is an abnormal growth of cells that starts in the pituitary gland. Cancer is extremely rare in the pituitary gland; most pituitary masses are benign, meaning they aren’t cancerous and will not spread to other parts of the body.

What does the pituitary gland do?

As the “master control gland,” the pituitary gland affects how hormones—those critical chemicals that control growth, metabolism, reproduction and mood—are made and function in the body.

It plays a key role in how hormones function within the body-- think of it as the boss of the other hormone-making glands. The pituitary gland is part of the endocrine system, which makes and sends hormones to tissues and organs through the bloodstream.

Where is the pituitary gland located?

The pituitary gland is a little organ—about the size of a pea—located near the lower part of the brain, just above the nasal passages.

How common are pituitary tumors?

Approximately 13,900 pituitary tumors are expected to be diagnosed in the United States in 2023, and most times they don't cause health problems. In fact, most people who have these tumors never even know it. There are several types of pituitary tumors—the most common one makes extra hormones the body doesn’t need and throws off the hormone balance in the body.

What causes pituitary tumors?

Scientists are still researching the specific causes of pituitary tumors, but researchers believe having the genetic condition multiple endocrine neoplasia type 1 (MEN1) may increase the risk for developing a tumor in the pituitary gland.

Types of pituitary tumors

Pituitary adenoma

Pituitary adenomas are benign, meaning they aren’t cancerous. These tumors don’t spread outside the skull, but they can grow into areas near the gland itself, like nearby tissues, blood vessels, nerves and sinuses. These tumors also tend to make more of a certain hormone than the body needs. 

Adenomas can be broken down into two categories based on size, as listed below.

Pituitary microadenoma

Smaller than one centimeter across, these tumors might cause symptoms if they make too much of a certain hormone. Many people have microadenomas that go unnoticed, because they’re small and don’t disrupt hormone levels enough to cause issues. 

Pituitary macroadenoma

Larger than one centimeter across, these tumors may cause symptoms by pinching on the pituitary gland or structures nearby, like the optic nerve (supplies messaging from the eye to the brain). Like microadenomas, they may also boost too much of a certain hormone. 

Adenomas that are diagnosed are broken down into two categories based on how they affect hormone levels: 

Functional pituitary adenoma

Each hormone in the body has a specific function, and the type of hormone a tumor makes can have a big impact on signs and symptoms, as well as how the tumor is diagnosed and treated. Functional pituitary adenomas make more hormones than the body needs. 

Non-functional pituitary adenoma

These tumors, also called “null cell adenomas,” don’t boost more hormones than the body needs, but they cause symptoms from their physical presence, and might stop or slow hormone production. Roughly 22 percent to 54 percent of pituitary tumors diagnosed are non-functional adenomas.

Pituitary carcinoma

Pituitary carcinomas are cancerous tumors. These occur rarely, representing less than 0.2 percent of all pituitary gland tumors, and the average age at diagnosis is 44. Pituitary carcinomas tend to look like non-cancerous adenomas in a lab examination, and they function like non-cancerous adenomas. Because of this, it’s challenging to know when a pituitary tumor may become cancerous.

Rarely, a tumor can start growing—not in the pituitary gland itself—but nearby. These tumors, which tend to occur in children or young adults, can impact the pituitary gland by growing into it.

Pituitary carcinoma symptoms

Usually, the only telltale sign of a cancerous pituitary tumor is when it spreads to areas nearby: the brain, spinal cord, meninges (the covering of the brain and spinal cord) or bone in the head. These cancerous tumors are rare to begin with, and even more rarely do they spread to other organs like the liver, heart or lungs.

Pituitary tumor symptoms

The signs and symptoms of pituitary tumors may depend on its size, how it affects the hormones and which hormones it affects. 

General signs and symptoms of pituitary tumors may include:

  • Nausea and vomiting
  • Confusion
  • Dizziness
  • Seizures
  • Runny nose

Symptoms of non-functional pituitary tumors

While hormone production isn’t over-activated from these tumors, they might press on or damage parts of the pituitary gland. This can cause the pituitary gland to stop making one or more hormones. A non-functional pituitary tumor might result in symptoms like: 

  • Headache
  • Loss of some vision
  • Loss of body hair
  • Lower sex drive
  • Less frequent menstrual periods
  • Lower sex drive or impotence
  • Delayed growth and puberty development in adolescents

Symptoms of functional pituitary tumors

The symptoms of functioning pituitary tumors depend on which hormones the tumor is making, with examples listed below.

Prolactin is a hormone that causes a woman’s breasts to make milk during and after pregnancy. Too much prolactin may cause headaches, loss of vision, lower sex drive, or changes in menstrual periods or fertility. It may cause breasts to produce milk, even in women that aren’t pregnant or breastfeeding. In men, it may cause impotence. 

Adrenocorticotropic hormone (ACTH) prompts the adrenal glands to make a hormone called cortisol, which controls how the body deals with stress and uses sugar, fats and protein. Too much ACTH may cause headaches, loss of vision, weight gain in specific places, changes to skin color such as bruising or stretch marks, weaker bones, hair growth on the face, upper back or arms or mood changes.

Growth hormone, also called somatotropin, helps control how the body uses sugar and fat. Too much growth hormone may cause headaches, loss of vision, abnormal bone growth and joint pain, sweating, tingling in hands and fingers, snoring or extreme dislike or concern about parts of the body (dysmorphophobia).

Thyroid-stimulating hormone, also called thyrotropin, activates the thyroid gland to make other hormones that control growth, body temperature and heart rate. Too much thyroid-stimulating hormone may cause sweating, weight loss, shakiness, irregular heartbeat, frequent bowel movement or trouble sleeping.

Gonadotropin hormones, luteinizing hormone (LH) and follicle-stimulating hormone (FSH), regulate ovulation, estrogen, progesterone and testosterone levels, and how much sperm is made by the testicles.

Pituitary tumor diagnosis

Pituitary tumors are diagnosed through taking images of the area and testing the patient's blood and urine. Some of the tests that help diagnose these tumors are listed below.

  • A physical exam and health history
  • An eye exam 
  • A visual field exam to test central and peripheral vision
  • A neurological exam, or “neuro exam,” consisting of questions to check the brain, spinal cord and nerve function
  • Magnetic resonance imaging (MRI) to take detailed pictures of the brain and spinal cord 
  • Computed tomography (CT) scan to create images of the brain
  • A blood chemistry study, to look for higher or lower than normal amounts of certain substances, such as glucose
  • Blood tests to measure hormone levels
  • Urine test, where urine is collected over 24 hours to measure hormone levels 
  • Dexamethasone suppression tests, where blood or urine is examined for excess cortisol after one or more doses of dexamethasone is given
  • Venous sampling, where the amount of ACTH is measured from a sample of blood from pituitary veins
  • A biopsy, which removes tumor cells to check for signs of cancer

Pituitary tumor treatment

Standard treatment for pituitary tumors includes surgery, radiation therapy and drug therapy. Chemotherapy may be used for rare, cancerous tumors. 

The care team may include several physician and surgical experts in neurology, endocrinology and oncology to come up with the most appropriate treatment plan for a pituitary tumor. 

Pituitary tumor surgery

Many pituitary tumors can be removed surgically. A surgeon may gain access to the tumor by making incisions under the upper lip, at the bottom of the nose, through the nose or through the skull. After surgery, the care team may use radiation therapy or chemotherapy to kill any tumor cells that are left. 

Pituitary tumor radiation therapy

Radiation therapy kills tumor cells or keeps them from growing by using high-energy X-rays or other types of radiation. A type of radiation called stereotactic radiosurgery (SRS) may be used for pituitary tumors, where a machine aims a single large dose of radiation directly at the tumor. Though this procedure isn’t a surgery, it’s sometimes called “stereotaxic radiosurgery,” “radiosurgery” or “radiation surgery.”

Drug therapy for pituitary tumors

Medication may be used in order to stop a functioning pituitary tumor from making too many hormones, but only certain hormone issues can be treated this way.

Pituitary tumor chemotherapy

Chemotherapy uses drugs to kill cancer cells or stop them from dividing. This treatment may be used for pituitary carcinomas to ease symptoms and improve quality of life when radiation therapy and surgery don’t work well.

Beyond these options, new types of treatment are being researched in clinical trials. These clinical trials help researchers find out if new cancer treatments are safe and effective—or even better—than current treatment options. The care team may be able to help find and evaluate clinical trial options. Trials are supported by several organizations, including the National Cancer Institute (NCI), and several listing search services are available online, such as the National Cancer Institute's (NCI’s) Steps to Find A Clinical Trial.

Pituitary gland tumor survival rate

One way to estimate life expectancy is to review the five-year relative survival rate for that condition. A five-year relative survival rate shows the likelihood that a person with a specific condition may live for at least five years after diagnosis, compared with people who don't have that condition. The rate includes the life expectancy of patients who are still in treatment and those who’ve have finished treatment and have no further evidence of disease.

The NCI’s SEER Program bases the survival rate for pituitary gland tumors on whether the tumor is cancerous or not. The five-year relative survival rate for all pituitary tumors is 97 percent, while the five-year relative survival rate for patients with cancerous pituitary gland tumors is above 81 percent.

Keep in mind that the survival rate for pituitary tumors depends on a variety of factors, including the patient’s age, overall health and the extent of the disease, so the patient should always talk to his or her care team about his or her individual prognosis.

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