A pituitary tumor is a growth that develops in the pituitary gland. It can affect your vision, but it isn’t located in your eye.

Pituitary tumors are common, but most people never even know they have them.

These tumors are caused by an abnormal growth of cells in the pituitary gland, and they usually are not cancerous. Most people only know they have a pituitary tumor when it grows so large that it begins to cause vision issues.

This article will explore what a pituitary tumor is, what symptoms you might expect, and how these tumors are managed.

A pituitary tumor isn’t located in your eye, but it can affect your vision if it grows large enough.

Pituitary tumors are located within the pituitary gland. This is a pea-sized gland that is located in your brain, just behind your nasal cavity, between the roof of your mouth and your eyes. Sometimes called the master gland, the pituitary gland is responsible for making all sorts of hormones that help you grow and function on a daily basis.

More than 10,000 pituitary tumors are diagnosed each year in the United States alone.

When these tumors are smaller than 10 millimeters (mm), they are known as microadenomas and do not usually produce any symptoms. Tumors larger than 10 mm are called macroadenomas and can cause symptoms.

Some of the most common symptoms of pituitary tumors include:

  • weakness
  • weight changes
  • blood pressure fluctuations
  • sexual dysfunction
  • blurred or double vision
  • difficulty with eye movements
  • visual field loss
  • progressive vision loss
  • headaches
  • facial numbness or pain
  • dizziness
  • loss of consciousness

There is a misconception that pituitary tumors develop in the eye, as one of the main symptoms that can develop with a pituitary tumor is vision changes or eye pain.

This happens because the optic nerve fibers — the nerves that control the messages that go from your eyes to your brain — pass directly beneath the pituitary gland.

As pituitary tumors grow, they can put pressure on the structures around them, including the optic nerve. When pressure is placed on the optic nerve, it can disrupt the signals being sent between the eye and brain, resulting in vision changes or eye pain.

In addition to causing symptoms from the pressure these tumors place on the structures around them, pituitary tumors can also disrupt the balance of hormones in your body.

The pituitary gland makes or manages the production of all kinds of hormones in your body, including growth and thyroid hormones and those that regulate the water balance in your body. Changes in these hormone levels can cause a wide range of symptoms.

Balance is regulated by signals sent to your brain from areas all over your body.

The vestibular system in your inner ear plays a big role in maintaining balance, but your balance can also be affected by any condition that leads to dizziness or loss of consciousness — including pituitary tumors.

The pituitary gland plays a role in all sorts of hormone levels, including reproductive hormones. Both men and women can develop pituitary tumors, but they are a bit more common in women.

According to research from 2021, 56% of pituitary tumors diagnosed in the United States between 2004 and 2016 were found in women. They were also more common in older adults.

Family history and genetics also play a role in the development of these tumors. Pituitary tumors have been found to run in families, and are associated with a number of congenital or genetic medical disorders.

Pituitary tumors are usually diagnosed by accident. Referred to as incidental findings, these tumors are usually spotted during imaging studies and other tests that are being done to investigate another health condition or symptom.

If your healthcare professional suspects a pituitary tumor, they’ll ask about your personal and family history and perform a medical exam. You’ll also undergo blood testing to determine whether the tumor is affecting your hormone levels or any other body functions.

Your healthcare professional may also conduct imaging studies like MRI scans and test tissues taken from the tumor during a biopsy.

The majority of pituitary tumors are not cancerous.

They’re simply an overgrowth of normal cells that can cause symptoms due to their size and the pressure they place on surrounding structures. About a third of all pituitary tumors are nonfunctioning, meaning they don’t affect hormone levels. It’s the size and location of the tumor that cause issues.

Other pituitary tumors might be described as functioning adenomas, meaning they produce or affect the production of various hormones. These tumors aren’t usually cancerous, but they can lead to a wide range of symptoms based on the hormones they’re affecting.

Cancerous pituitary tumors, known as pituitary carcinomas, are rare. They may be confused with other types of tumors that might form in the same area, such as:

  • teratomas
  • germinomas
  • choriocarcinomas
  • Rathke cleft cysts
  • gangliocytomas
  • craniopharyngiomas

Much like functioning adenomas, cancerous pituitary tumors often affect hormone levels or production. They can appear with similar symptoms as functioning adenomas. Their size can also mimic symptoms of nonfunctioning adenomas because of pressure placed on surrounding structures as the tumors grow.

The only way to differentiate between adenomas and carcinomas in the pituitary gland is to observe for tumor activity spreading into other areas of the brain.

Pituitary carcinomas usually spread to areas in the:

  • brain
  • spinal cord
  • the layer covering the brain and spinal cord (meninges)
  • bones around the pituitary gland

Metastasis — cancer cells spreading to other areas of the body — is rare with pituitary carcinomas.

There are no specific diets associated with the development or prevention of pituitary tumors.

However, a 2021 study suggests that intermittent fasting, periodic fasting, and plant-based diets may all have positive impacts on helping reduce tumor activity.

Pituitary tumors don’t always need to be treated. If they’re affecting your hormone levels or your symptoms are interfering with your daily life, your healthcare professional may suggest treatment.

Treatment options depend on your overall health and the degree of your symptoms.

Surgical removal of the tumor is one option, and radiation may be used alone or in combination with therapy to shrink the tumor. Your healthcare professional may also prescribe medications to reduce or block excessive amounts of hormones produced by your pituitary tumor.

Pituitary tumors develop in the space just behind your eye, where the optic nerves from both eyes crisscross on the way to the brain. When these tumors become too large, they can press on the optic nerve fibers and cause vision changes or issues.

Most people don’t know they have pituitary tumors. They’re typically found by accident, during testing for another health condition or symptom.

If you have a pituitary tumor, your healthcare professional may decide to monitor it for growth before treating or removing it. If your symptoms are affecting your daily activities, treatment might be necessary.