Your pathology report for inflammatory polyp of the colon

by Jason Wasserman MD PhD FRCPC
July 24, 2025

An inflammatory polyp is a non-cancerous growth that forms on the inner lining of the colon or rectum. These polyps are caused by inflammation or tissue injury and are sometimes called pseudopolyps because they are not true neoplasms (tumours) but rather a reaction to damage. Inflammatory polyps can develop anywhere in the colon, but they are most commonly found in the sigmoid colon and rectum.

What causes an inflammatory polyp?

Inflammatory polyps form when the lining of the colon becomes injured or inflamed and the tissue tries to heal. This healing response can lead to the growth of polyp-like projections. There are several conditions that can cause this type of inflammation, including:

  • Inflammatory bowel disease (IBD): People with ulcerative colitis or Crohn’s disease are more likely to develop inflammatory polyps, especially in areas of the colon that have been inflamed for a long time. These polyps are more common in the rectum.

  • Infection: Some infections of the colon, especially those that cause diarrhea or inflammation, can lead to the formation of temporary inflammatory polyps.

  • Constipation and irritation: Straining or prolonged constipation may irritate the colon wall and cause inflammation that can result in a polyp.

  • Ischemia: Reduced blood flow to the colon can damage the lining and lead to inflammation.

What are the symptoms of an inflammatory polyp?

Many inflammatory polyps cause no symptoms and are found incidentally during a colonoscopy performed for another reason.

However, some people may experience:

  • Diarrhea or loose stools.

  • Mucus in the stool.

  • Rectal bleeding.

  • Abdominal discomfort.

  • A sensation of incomplete bowel emptying.

These symptoms are usually related to the underlying inflammation rather than the polyp itself.

How is the diagnosis made?

The diagnosis of an inflammatory polyp is typically made after a tissue sample is removed during a colonoscopy. Because these polyps often stick out from the surface of the colon, they can be seen during the procedure and removed completely. This procedure may be called a biopsy or polypectomy, depending on the size of the polyp. The tissue is then examined by a pathologist under the microscope.

What does an inflammatory polyp look like under the microscope?

Under the microscope, inflammatory polyps show a combination of features related to inflammation and healing:

  • Normal glands with inflammation: The glands that line the inside of the colon are typically present but surrounded by large numbers of inflammatory cells, especially neutrophils and plasma cells.

  • Reactive changes: The glands may appear distorted or irregular due to the healing process. Pathologists describe this appearance as “reactive.”

  • Granulation tissue: In larger polyps, the normal mucosa may be replaced by a healing tissue called granulation tissue. This type of tissue contains new blood vessels and inflammatory cells.

  • Erosion: The surface of the polyp may show areas where the protective cell layer is damaged or missing. This is called erosion and is a sign of recent injury.

  • Dysplasia: Dysplasia is a precancerous change in the cells. It is rarely seen in inflammatory polyps but may be present in people with long-standing inflammatory bowel disease. If dysplasia is present, it will be noted in your pathology report because it may change follow-up and treatment.

Is an inflammatory polyp cancer?

No. An inflammatory polyp is not cancer and does not mean you have cancer. However, people with inflammatory bowel disease may have an increased risk of developing colorectal cancer over time. The presence of inflammatory polyps in this setting is a sign of previous inflammation but does not directly increase your cancer risk.

What happens next?

Most inflammatory polyps do not require any further treatment once they are removed. However, your doctor may recommend follow-up colonoscopies if:

  • You have a known history of IBD.

  • The polyp was large or difficult to remove.

  • Dysplasia was found in the polyp.

Your overall care will depend on the underlying cause of the inflammation and whether any other changes were seen during your colonoscopy.

Questions to ask your doctor

  • What caused the inflammation that led to the polyp?

  • Was the polyp completely removed?

  • Did the pathologist see any signs of dysplasia?

  • Do I need a follow-up colonoscopy?

  • Does this finding change how my inflammatory bowel disease is managed?

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