Diverticular disease

by Jason Wasserman MD PhD FRCPC
April 4, 2024

Diverticular disease is a medical condition associated with the formation of small, bulging pouches in the digestive tract. They are most frequently found in the large intestine (colon). Diverticular disease encompasses a spectrum of conditions, from diverticula without inflammation (diverticulosis) to diverticula with acute inflammation and possibly infection of these pouches (diverticulitis).

What parts of the digestive tract are commonly affected by diverticular disease?

Diverticular disease most commonly occurs in the sigmoid colon, part of the large intestine located near the end of the digestive tract, just before the rectum. However, diverticular disease can also occur in the descending colon, which is the section of the large intestine that runs downward on the left side of the abdomen. While the sigmoid colon is particularly prone to the development of diverticula due to high internal pressure and muscular actions, the descending colon can also be affected, especially in individuals with a long-standing low-fiber diet, leading to increased bowel pressure throughout the colon. Although less common, diverticula can also develop in other parts of the digestive tract such as the appendix.

What causes diverticular disease?

The exact cause of diverticular disease is not fully understood, but it is believed to be related to a low-fiber diet, which can lead to constipation and increased pressure within the colon. This pressure may cause the formation of diverticula by pushing the lining of the colon out through weak spots in the colon’s muscular layer.

What are the symptoms of diverticular disease?

Many people with diverticular disease do not experience symptoms. When symptoms do occur, they may include mild cramps, bloating, and constipation. In the case of diverticulitis, symptoms are more severe and can include intense abdominal pain, fever, nausea, and a marked change in bowel habits.

How is this diagnosis made?

The diagnosis of diverticular disease is often made through a combination of patient history, physical examination, and imaging tests such as a computed tomography (CT) scan or colonoscopy. These tests help identify the presence of diverticula and assess any complications.

Microscopic features of this disease

Under a microscope, diverticula appear as outpouchings of the colon wall. In diverticulitis, there is evidence of acute inflammation around these pouches, including infiltration by immune cells such as neutrophils and lymphocytes, and possibly the formation of microabscesses.

Diverticular disease with diverticulitis


Diverticulitis represents a complication of diverticular disease where the diverticula becomes inflamed or infected. This condition is more serious and is associated with symptoms such as abdominal pain, fever, and gastrointestinal disturbances.


Perforation refers to a tear or hole in the wall of a diverticulum, leading to the leakage of intestinal contents into the abdominal cavity, which can cause peritonitis, a serious infection requiring prompt medical intervention. It’s a severe complication of diverticulitis that significantly increases the risk of mortality and morbidity.

Serosal abscess

A serosal abscess is an abscess or a collection of inflammatory cells that forms on the outer surface of the colon in response to the spread of infection from an inflamed or perforated diverticulum. It’s a significant condition because it indicates a localized infection that, if not properly managed, can lead to more extensive abdominal infections or necessitate surgical intervention to resolve.

About this article

Doctors wrote this article to help you read and understand your pathology report. Contact us if you have questions about this article or your pathology report. For a complete introduction to your pathology report, read this article.

Other helpful resources

Atlas of pathology
A+ A A-