What is an adenoma?


An adenoma is a noncancerous growth made up of glandular cells. Glandular cells are special cells found throughout the body that produce and release substances such as mucus, enzymes, and hormones to help organs work properly. Although adenomas are not cancerous, some types can develop into cancer over time. For this reason, adenomas are often carefully monitored or removed, depending on their location.

Adenoma

What causes an adenoma?

The cause of an adenoma depends on the type of adenoma and where it grows. In many cases, adenomas form because of a combination of genetic, environmental, and hormonal factors.

For example:

  • Colon adenomas (polyps) may be influenced by diet, family history, and genetics.

  • Breast or thyroid adenomas may develop under the influence of hormones.

  • Chronic irritation or inflammation can increase the risk of adenomas in some organs.

In most patients, no single cause can be identified.

Where are adenomas found?

Adenomas can form in many organs throughout the body, including the colon, stomach, thyroid gland, adrenal glands, salivary glands, kidneys, breast, bladder, uterus (endometrium), and cervix.

Common types of adenomas include:

What is the difference between an adenoma and a polyp?

An adenoma is a specific type of tumour made up of glandular cells.

A polyp is a general term that describes any growth projecting from a mucosal surface (such as the lining of the colon or stomach). Some polyps are adenomas, but others may be inflammatory or made up of different types of cells. In other words, all adenomas are polyps when they grow in a mucosal surface, but not all polyps are adenomas.

What is the risk of an adenoma turning into cancer?

Most adenomas remain benign, but some can progress to cancer.

The risk depends on:

  • Type of adenoma – for example, some colon adenomas carry a higher risk than others.

  • Size of the adenoma – larger adenomas are more likely to contain abnormal cells.

  • Microscopic changes – if your pathologist describes dysplasia (abnormal cells with the potential to become cancer), the risk of cancer is higher.

  • Location – adenomas in certain organs (such as the colon or endometrium) have a higher chance of progressing to cancer.

This is why colon adenomas, for example, are usually removed during colonoscopy—to prevent them from turning into colorectal cancer.

Why are adenomas important in pathology?

Pathologists examine and describe adenomas in reports because they are common and clinically important. While most are harmless, some require treatment or follow-up to prevent progression to cancer. Identifying an adenoma in a pathology report helps your healthcare team decide whether observation, removal, or additional treatment is needed.

Questions to ask your doctor

  • What type of adenoma was found in my pathology report?

  • Does my adenoma have any features that increase the risk of cancer?

  • Will this adenoma need to be removed, or can it just be monitored?

  • Do I need follow-up tests, such as a colonoscopy or imaging?

  • Does this diagnosis increase my risk for other adenomas or cancers?

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