by Jason Wasserman MD PhD FRCPC
March 1, 2023
Barrett’s esophagus is a condition where the tissue that covers the inside surface of the esophagus changes to look like the tissue normally found inside the small intestine. Barrett’s esophagus is considered a precancerous condition because it can overtime change into a type of esophageal cancer called adenocarcinoma.
Barrett’s esophagus is caused by long-standing acid reflux disease (also known as gastroesophageal reflux disease or “GERD”). When acid from the stomach enters the esophagus it damages the squamous cells that cover the inside surface of the esophagus. Pathologists describe this as reflux esophagitis. Over time, the injured squamous cells are replaced by cells normally found in a part of the digestive system called 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.
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.
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 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 grade dysplasia and high grade dysplasia.
Barrett’s esophagus with low grade dysplasia is a precancerous condition associated with an increased risk of developing adenocarcinoma compared to patients who have Barrett’s esophagus but no dysplasia. In low grade dysplasia, the cells appear abnormal in shape or colour but the pattern of growth is similar to Barrett’s esophagus without dysplasia.
Barrett’s esophagus with high grade dysplasia is a precancerous condition associated with an increased risk of developing adenocarcinoma compared with patients who have Barrett’s esophagus but no dysplasia or low grade dysplasia. In high grade dysplasia, both the cells and the pattern of growth are abnormal. In particular, the glands appear crowded or back-to-back in a pattern pathologists describe as cribriform. Mitotic figures (dividing cells) and necrosis (dead cells) may also be seen.