Barrett’s esophagus

by Jason Wasserman MD PhD FRCPC
April 19, 2022


What is Barrett’s esophagus?

Barrett’s esophagus is a non-cancerous condition where the cells that line the inside of the esophagus change to look like the cells that normally line the inside of the small intestine. Barrett’s esophagus is associated with long-standing acid reflux disease. The presence of an abnormal pattern of growth called dysplasia in Barrett’s esophagus increases the risk of developing a type of esophageal cancer called adenocarcinoma.

What causes Barrett’s esophagus?

Barrett’s esophagus is caused by long-standing acid reflux disease (this condition is also called “GERD”). When acid from the stomach enters the esophagus it damages the squamous cells that cover the inside of the esophagus. Pathologists describe this as reflux esophagitis. Over time, the injured squamous cells are replaced by cells normally found in the small intestine. These intestinal-type cells are designed to protect tissue from the strong acids in the stomach. The change from squamous cells to intestinal-type cells is called intestinal metaplasia.

How do pathologists make the diagnosis of Barrett’s esophagus?​

Barrett’s esophagus is almost always diagnosed first on a biopsy. The biopsy is usually performed because the person has symptoms consistent with acid reflux disease. The diagnosis may also be made after a larger piece of tissue is removed in a procedure called an endoscopic mucosal resection.

What does Barrett’s esophagus look like under the microscope?

When examined under the microscope, the tissue shows intestinal-type cells covering the inside of the esophagus. In particular, your pathologist will look for a specialized type of cell called a goblet cell to make the diagnosis of Barrett’s esophagus. Goblet cells are large round cells that appear blue when examined under the microscope because they are full of a substance called mucin. These types of cells are normally found in the small intestine but are not found in the normal, healthy esophagus.

Barrett's esophagus

Barrett’s esophagus under the microscope.

What is dysplasia and why is it important?

Barrett’s esophagus which has been present for many years increases the risk of developing an abnormal pattern of growth called dysplasia. Dysplasia is important because it can lead to a type of esophageal cancer called adenocarcinoma. Pathologists divide dysplasia into two levels – low and high – and the risk of developing cancer is greater when high grade dysplasia is seen.

What is a margin?

A margin is normal tissue that surrounds an area of abnormal tissue and is removed with the abnormal tissue at the time of surgery. When a part of the esophagus is removed to treat Barrett’s esophagus, the surgeon will try to remove a small amount of normal esophagus (or sometimes stomach) to ensure that no abnormal tissue is left behind. High-grade dysplasia close to or at the cut edge of the tissue is associated with a higher risk of the disease coming back in the future. Pathology reports for small tissue samples such as biopsies do not include margins.

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