This article was last reviewed and updated on May 14, 2019
by Ipshita Kak, MD FRCPC
The normal colon
The colon is a part of the gastrointestinal tract which also includes the mouth, esophagus, stomach, small bowel, and anus. The colon is a long hollow tube that starts at the small bowel and ends at the anal canal. The colon is divided into sections which include the cecum, ascending colon, transverse colon, descending colon, sigmoid colon, and rectum.
The functions of the colon are to absorb water from the food that we eat and to move waste out of the body.
The colon is made up of five layers of tissue:
What is a tubular adenoma?
Why is this important? Tubular adenomas are important because some will develop changes that can lead to a type of colon cancer called adenocarcinoma over time.
Examination of the colon in a procedure known as a colonoscopy and removal of any polyps has been shown to reduce the risk of developing colon cancer in older adults.
The type, size, and number of polyps removed at your first colonoscopy will determine the period within which your doctor will ask you to come back for a follow-up endoscopy.
When examined under the microscope, tubular adenomas are made up of cells that show an abnormal pattern of growth. Pathologists call this abnormal pattern of growth dysplasia. Dysplasia in the colon is important because it is considered a precancerous or precursor condition that can turn into a cancer over time.
In the colon, pathologists divide dysplasia into two categories called low grade dysplasia and high grade dysplasia. All tubular adenomas show at least low grade dysplasia. Your pathologist will carefully examine your tissue sample to look for any high grade dysplasia.
Why is this important? The risk for developing cancer is greater with high grade dysplasia.
In the colon, a margin is any tissue that was cut by the surgeon in order to remove the tubular adenoma from your body. Many tubular adenomas grow on a piece of tissue called a stalk and the adenoma is removed by cutting the stalk. In these cases, the margin is the part of the stalk that is cut.
Tubular adenomas are often removed and sent to pathology as multiple pieces (fragments) of tissue. In some of these cases, it will not be possible for your pathologist to determine which piece is the real margin and the changes seen at the margin will not be described in your report.