Granuloma Characteristic in a Biopsy

If this characteristic is found in a biopsy, it indicates Crohn's disease

Biopsy Slides
A biopsy sample may be put onto a slide, where it can be stained and examined under a microscope. Image © PhotoStock / Israel Cultura / Getty Images

A granuloma is a microscopic collection of cells. Granulomas form in response to an infection or an inflammatory state. Granulomas can form in several different areas of the body, including the lungs. In the digestive system, when granulomas are seen, it is sometimes the result of inflammatory bowel disease (IBD).

Granulomas In Crohn's Disease

Granulomas are not specific to Crohn's disease, but if seen are helpful in distinguishing between ulcerative colitis and Crohn's disease. But when a granuloma is found, and the patient has symptoms consistent with IBD, it can help a physician make a diagnosis of Crohn's disease. A granuloma cannot be seen during a colonoscopy because it is not a visible mass or nodule.

It's estimated that 15% to 25% of people with Crohn's disease have granulomas. There is a slight tendency for more women to have granulomas than men: one study showed 57% of the Crohn's disease patients with granulomas were women. This type of Crohn's disease is sometimes called granulomatous colitis. Granulomas are not seen on intestinal or colonic biopsies of patients with ulcerative colitis.

How Are Granulomas Found?

During an endoscopy procedure (such as a colonoscopy, upper endoscopy, or a sigmoidoscopy), small pieces of tissue called biopsies are taken. These pieces of tissue can be tested in a variety of ways. They can be stained so that the microscopic parts of the tissue are better seen under a microscope by a pathologist. When the pathologist looks at the intestinal tissue biopsy, granulomas or other varieties of cells might be seen. 

What Does It Mean If You Have Granulomas?

Having granulomas is generally thought to indicate that it is Crohn's disease that is present, rather than a different form of IBD. Whether or not the presence of granulomas means something as to how the Crohn's disease is going to progress is still being studied. Some studies have shown that people with granulomas tend to get diagnosed fairly early in the disease process. Unfortunately, there also tended to be an association between granulomas and a more complex form of Crohn's disease that required surgery, hospitalizations to treat a flare-up, and complications such as strictures.  

Why They Form

Because granulomas are often found in people who are first presenting with Crohn's disease, there has been some speculation as to why this is the case. One reason that has been presented is that the granuloma is the result of the body trying to deal with the cause of the Crohn's disease. We don't know what causes Crohn's disease, and in fact there are probably many causes, working in conjunction to cause inflammation. The idea is that for some particular causes (and we don't know what those are), the body may form a granuloma around whatever it is that is precipitating the inflammation. The granuloma is an attempt to deactivate the trigger, or render it harmless.

To take this idea one step further, because granulomas are found more often in women, this leads to the hypothesis that there could be hormones involved. Of course, none of this is known for certain, and, like many aspects of IBD, granulomas are still a topic that is under study. 

Pronunciation: gran-yoo-LO-muh

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