Adenomas are noncancerous tumors. They may grow along your adrenal, parathyroid or pituitary glands. If your adenoma is small, your healthcare provider may use a wait-and-see approach. In more severe cases, you may need surgery to remove the adenoma.


What are adenomas?

An adenoma is a benign (noncancerous) tumor. Adenomas start in the epithelial tissue, the tissue that covers your organs and glands. These tumors grow slowly and look like small mushrooms with a stalk.


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What are the types of adenomas?

Adenomas most commonly grow along your glandular organs. Glandular organs produce and release chemicals called hormones. Hormones regulate many of your body’s functions.

Adenomas may also grow in other parts of your body. Different types of adenomas include:

Many adenomas are nonfunctioning, meaning they don’t produce hormones. You might not have any noticeable symptoms. Functioning adenomas produce excess hormones.

What are the growth patterns of adenomas?

Healthcare providers categorize adenomas based on how they grow. They can be:

  • Tubular: Grows in a round or oval shape and is most common in small (less than ½ inch) adenomas.
  • Villous: Grows in a shaggy, cauliflower-like pattern and is most common in larger adenomas.
  • Tubulovillous: A mixture of the two growth patterns.

Tubular adenomas are more common than villous adenomas. They are less likely to turn into cancer than villous adenomas.


How do adenomas affect my body?

By definition, adenomas are not cancerous. However, you should view them as precancerous. They can sometimes turn into cancer. It’s important for your healthcare provider to monitor adenomas and treat them if necessary.

Even though adenomas are benign tumors, they can lead to health complications. Some adenomas press on surrounding organs or disrupt hormone production as they grow.

Symptoms and Causes

What causes adenomas?

Often, the exact cause of an adenoma is unknown. Factors that can affect your risk of adenomas include:

  • Age: Adults in their 30s or 40s are more likely to develop pituitary adenomas.
  • Ethnic background: People of Ashkenazi Jewish descent have a higher risk of adenomas.
  • Gene mutations (changes): Genetic conditions like multiple endocrine neoplasia type 1 (MEN1) make adenomas more likely. These types of gene mutations are hereditary (inherited from your biological parents).
  • Genetic diseases: Some adenoma causes, such as familial adenomatous polyposis (FAP), run in families.
  • Sex: Women are twice as likely to develop parathyroid adenomas.


What are the symptoms of adenomas?

If an adenoma is small, it may not cause any symptoms. Adenoma symptoms can vary greatly depending on the adenoma’s location.

In general, symptoms of larger adenomas may include:

Diagnosis and Tests

How are adenomas diagnosed?

To diagnose an adenoma, your healthcare provider will complete a physical exam and medical history. You may also need one or more imaging tests, such as a CT scan, MRI scan or PET scan.

Your healthcare provider may also order a biopsy of the adenoma. During a biopsy, your healthcare provider takes a small tissue sample to send to a laboratory. The laboratory analyzes the sample and rules out or confirms the presence of an adenoma.

Management and Treatment

How are adenomas treated?

If an adenoma is small and not causing any health complications, your healthcare provider may recommend a “wait-and-see” approach. With this approach, also called surveillance, you don’t get treatment right away. Instead, you follow up periodically with your healthcare provider. During these follow-up visits, your healthcare provider checks that the adenoma has not grown or changed.

If an adenoma is causing hormone problems, your healthcare provider may prescribe medications to control the symptoms. If the adenoma is large or causing significant health problems, your healthcare provider may recommend surgery to remove the adenoma.


How can I reduce my risk of adenomas?

Some risk factors for adenomas are not controllable. However, you can improve your chances of staying healthy by getting regular health screenings. If you have a higher risk of developing an adenoma, ask your healthcare provider how often you should receive screenings.

You can also improve your health by:

  • Avoiding smoking.
  • Eating plenty of fruits, vegetables and whole grains.
  • Exercising regularly.
  • Limiting alcohol consumption.

Outlook / Prognosis

What is the outlook for people with adenomas?

If you receive treatment for an adenoma, the outlook is typically very good. Many types of adenomas respond well to treatment and do not turn into cancer.

Some adenomas, such as adenomas in the colon, carry a higher risk of cancer. It’s important to seek treatment right away if you suspect you have an adenoma. Having a colonoscopy when your provider recommends it can catch adenomas in the colon while they’re small.

Living With

What else should I ask my healthcare provider?

You may want to ask your healthcare provider:

  • How often do I need to return for screenings?
  • What can I do to lower my risk of developing another adenoma?
  • What symptoms might indicate I have another adenoma?
  • How does having an adenoma affect my overall health risks?

A note from Cleveland Clinic

Adenomas are benign (noncancerous) tumors. However, you should treat adenomas as precancerous because they may turn into cancer if left undetected. The severity of an adenoma can vary greatly, depending on its size and location. If an adenoma is small, you may not need treatment right away. For a larger or problematic adenoma, your healthcare provider may recommend surgery to remove it. Most adenomas that are caught early do not turn into cancer.

Medically Reviewed

Last reviewed on 11/22/2021.

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