Pituitary adenomas are the most common pituitary tumors. They’re usually noncancerous and grow slowly. Some rarer tumors, such as pituitary carcinoma, can spread quickly.

Your pituitary gland is a small organ found at the base of your brain that secretes nine types of hormones.

Many types of tumors can develop on or near your pituitary gland. Tumors can compress the surrounding brain tissue or create extra hormones.

Pituitary adenomas are the most common pituitary tumors and the fourth most common brain tumors. They’re almost always noncancerous and grow slowly.

Autopsy studies suggest that small pituitary adenomas 3–5 millimeters (mm) across that don’t cause symptoms are extremely common in the general population.

This article examines how fast the most common types of pituitary tumors usually grow.

Most pituitary tumors grow slowly. Even if your doctor tells you that your tumor doesn’t require treatment, you’ll still need to have regular follow-ups to track how the tumor changes over time. In rare cases, some types of tumors that are typically slow-growing can transform into cancer.

Pituitary adenoma

According to the American Association of Neurological Surgeons, pituitary adenomas are the most common diseases that affect the pituitary gland.

Pituitary adenomas are usually noncancerous and grow slowly. Small tumors are called microadenomas and large tumors are called macroadenomas.

When adenomas grow larger than about half an inch across, they can grow upward and compress your brain tissue and optic nerves.

In a 2019 study from South Korea, researchers examined the growth rate of 59 untreated pituitary adenomas from 2003–2014. Here’s a summary of their results:

Volume1.83±2.97 mL2.85±4.47 mL
Diameter13.77±6.45 mm15.75±8.08 mm

The average growth rate of the tumors was 0.33±0.68 milliliters (mL) per year at an average follow-up period of 46.8±32.1 months. 0.33 mL is roughly equivalent to 6–7 drops with an eyedropper.

About a quarter of the tumors in their study showed growth. Larger tumor size was predictive of future growth.

Adenoma name changes

In 2021, the World Health Organization (WHO) revised its classification of central nervous system and endocrine tumors. They have renamed pituitary adenomas to pituitary neuroendocrine tumors.

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Pituitary carcinoma

Adenomas that spread beyond the pituitary gland used to be referred to as pituitary carcinoma. In the WHO’s newest classification system, they’re now called metastatic pituitary neuroendocrine tumors.

Pituitary carcinoma only makes up about 0.12% of pituitary tumors. These tumors can grow rapidly. Some researchers define rapid as growing more than 20% of their original size in less than 6 months.

Pituitary carcinoma requires prompt treatment, which might include:

It’s common for people with pituitary carcinoma to need multiple surgeries. Researchers have reported 5-year survival rates of more than 67%.

Rathke cleft cysts

Rathke cleft cysts are noncancerous tumors that have a liquid core and develop between your pituitary gland and the base of your brain. Autopsy studies suggest that they may be very common, existing in as many as 22% of people.

In a 2021 study from Sweden, researchers examined the growth rate of Rathke cleft cysts among 434 people.

The researchers found that:

  • Cysts smaller than 10 mm not operated on didn’t progress at a 5-year follow-up. Only 1 out of 204 people had a cyst grow larger than 10 mm.
  • Larger cysts that weren’t surgically removed decreased in size slightly over 5 years.
  • Progression was most likely with cyst remnants after surgery or reoccurring cysts.


Craniopharyngioma is an extremely rare tumor that usually occurs in children from 5–14 and adults from 50–74. They’re noncancerous and tend to grow slowly. The WHO now recognizes two separate types:

  • adamantinomatous craniopharyngioma
  • papillary craniopharyngioma

In a 2016 study, researchers examined the growth patterns of craniopharyngioma treated between 2000 to 2015.

To treat their tumors, 27 people underwent surgery and radiation therapy. About 40% of the people had tumor growth within 1 year of radiation therapy.

Half of the tumors that grew expanded by a volume of 4.1 mm above their postsurgical volume.

Not all pituitary tumors require treatment. Surgery is often required for tumors that are:

  • growing rapidly
  • compressing other structures
  • secreting hormones

Even if your doctor doesn’t think that you need surgery, they’ll likely want to continue to monitor your tumor with regular imaging to see how it changes over time.

Some types of pituitary tumors respond well to medications and don’t require surgery. One example is prolactinomas. Prolactinomas are pituitary adenomas that secret the hormone prolactin. A class of medication called dopamine agonists can shrink these tumors in about 80% of people.

How long can you live with a pituitary tumor?

Some pituitary tumors do not require treatment and are small enough that they don’t compress your brain tissue. Your lifespan may not be affected if your pituitary tumor remains small. Many pituitary tumors likely go undiagnosed because they do not cause symptoms.

Pituitary adenomas often have a good outlook if they’re treated promptly with surgery or medications and aren’t secreting hormones. Tumors that secret hormones affect many aspects of your health, but they’re also often treatable.

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Most pituitary tumors are pituitary adenomas. These tumors aren’t usually cancerous and tend to develop slowly. Doctors may need to remove them surgically if they compress other structures in your brain and cause symptoms.

Some other types of tumors such as pituitary carcinoma can develop rapidly and require prompt treatment. It’s important to follow up with your doctor regularly if you have a pituitary tumor even if you have a type that doesn’t typically progress quickly.