Cardiac type mucosa is a type of tissue that lines part of the stomach and the area where the esophagus meets the stomach — a region called the gastroesophageal junction. It is made up of tightly packed glands that produce mucus, which helps protect the lining from stomach acid. The word “cardiac” in this context has nothing to do with the heart — it refers to the cardia, which is the uppermost part of the stomach. A small amount of cardiac type mucosa at the gastroesophageal junction is a normal finding in pathology reports from this region.
Under the microscope, cardiac type mucosa appears as closely packed, simple glands lined by a single layer of cells. These cells are tall and column-shaped, with pale cytoplasm filled with mucin — the substance that forms mucus. Unlike other parts of the stomach — such as the body and fundus, which contain acid-producing cells and enzyme-secreting cells — cardiac type mucosa contains only mucus-producing glands. This gives it a distinctive, uniform appearance that is recognizable to a pathologist even without special stains.
Cardiac type mucosa with chronic inflammation means that immune cells — specifically lymphocytes and plasma cells — were found within the tissue when it was examined under the microscope. This is a common finding in biopsies from the gastroesophageal junction. The most frequent causes include:
Chronic inflammation in cardiac type mucosa is not cancer and does not mean cancer is present. However, treating the underlying cause — whether that is H. pylori eradication or acid suppression for GERD — is important to reduce ongoing tissue damage.
Finding cardiac type mucosa in the esophagus is a significant pathological finding that requires careful interpretation. The normal lining of the esophagus is made up of flat squamous cells, not the mucus-producing glandular cells of cardiac type mucosa. When cardiac type mucosa is identified in the lower esophagus, it indicates that the normal squamous lining has been replaced by glandular tissue — a change driven by repeated acid damage from GERD.
This replacement of one cell type by another is called metaplasia. Cardiac type mucosa in the esophagus is considered an early step in the development of Barrett’s esophagus. When this cardiac-type glandular lining subsequently develops intestinal metaplasia — a further change in which cells resembling those of the small intestine, including characteristic goblet cells, appear — this meets the criteria for a diagnosis of Barrett’s esophagus.
Barrett’s esophagus is a precancerous condition that increases the risk of developing esophageal adenocarcinoma, which is why regular surveillance endoscopy with biopsies is recommended for patients who have it.
Cardiac type mucosa with intestinal metaplasia means that some of the glandular cells have changed to resemble cells normally found in the small intestine. This change is identified under the microscope by the presence of distinctive goblet cells — large, mucin-filled cells with a rounded, cup-like shape that are characteristic of intestinal lining but are not normally found in the stomach or esophagus.
The clinical significance of this finding depends on where the biopsy was taken: