Causes, Risk Factors, and Prevention of Pituitary Tumors

Learn about the causes and risk factors for pituitary tumors and if there are things you can do that might help lower your risk.

What causes pituitary tumors?

We don’t know exactly what causes most pituitary tumors. But we do know about some of the changes that can happen inside pituitary cells that can cause them to form tumors, most of which are pituitary adenomas.

How gene changes (mutations) can lead to tumors

Researchers have made great progress in understanding how certain gene changes in pituitary cells can lead to them forming a pituitary tumor. For example, some genes contain instructions for controlling when our cells grow and divide. Changes in these genes can lead to them growing out of control and forming tumors.

To learn more, see Oncogenes, Tumor Suppressor Genes, and DNA Repair Genes.

Inherited vs. acquired gene changes in pituitary tumors

Gene changes that cause cancer can be:

• Inherited, passed down from a parent.
• Acquired, happening either because of damage inside a cell or by chance.

Most gene changes in pituitary tumors are acquired during life. Sometimes acquired changes occur in genes such as GNAS and USP8. These gene changes are much more common in some types of pituitary adenomas than in others.

Inherited changes have been found in the MEN1, CDKN1B, PRKAR1A, and AIP genes. If these changes are found in someone with a pituitary tumor, they and their family members might consider having genetic testing to find out if they are affected.

Risk factors for pituitary tumors

A risk factor is anything that increases a person’s chances of getting a disease. But having a risk factor, or even many risk factors, does not mean that you will get the disease. And many people who get the disease might have few or no known risk factors.

Pituitary tumors have only a few known risk factors.

Family history

Rarely, pituitary tumors can run in families. They might be found as part of a genetic syndrome, often along with other types of tumors (see below).

Sometimes, though, the cause of pituitary tumors that run in families is not known.

Genetic syndromes

Pituitary tumors can sometimes be a part of a syndrome that often includes an increased risk of other types of tumors as well. These syndromes are caused by changes in a person’s genes that are often inherited from a parent. You can learn more in Family Cancer Syndromes.

Multiple endocrine neoplasia, type 1 (MEN1): This is a hereditary condition in which people have a very high risk of developing tumors of the pituitary, parathyroid, and pancreas. This syndrome is caused by changes in the MEN1 gene, and it is passed on to about half of the children of an affected parent.

Multiple endocrine neoplasia, type 4 (MEN4): This rare syndrome is very similar to MEN1, in that people with MEN4 have increased risks of pituitary tumors and certain other tumors. But MEN4 is caused by changes in the CDKN1B gene, which is most often inherited from a parent.

McCune-Albright syndrome: People with this syndrome often have brown patches on their skin called café-au-lait spots and develop many bone problems. They can also have hormone problems and pituitary tumors. This syndrome is caused by changes in the GNAS gene, which aren’t inherited but occur before birth.  

Carney complex: This is a rare syndrome in which people have changes in skin coloring, as well as a high risk of some types of benign (noncancerous) tumors, including pituitary tumors. Most cases are caused by inherited changes in the PRKAR1A gene, but some are caused by changes in other genes that have not yet been identified.

Familial isolated pituitary adenoma (FIPA): In this syndrome, only pituitary tumors run in the family. This syndrome is sometimes caused by changes in the AIP gene, although in many cases the gene changes that cause it aren’t yet known.

Can pituitary tumors be prevented?

Certain lifestyle changes such as staying at a healthy weight or not smoking can lower the risk for many types of cancer. But pituitary tumors have not been linked with any known outside risk factors. Because of this, there is no known way to prevent these tumors.

For people at increased risk of pituitary tumors because of certain inherited syndromes, there might be ways to find and treat them early, before they cause problems. To learn more, see Pituitary Tumors Early Detection and Diagnosis.