The stomach is part of the gastrointestinal tract. When we eat, food enters the mouth and travels down the esophagus into the stomach. Once in the stomach, the food is mixed with a strong acid which breaks the food down into very small particles. This process is called digestion. The digested food particles are then either absorbed into the bloodstream or removed from the body as waste.
The tissue on the inner surface of the stomach is made up of specialized epithelial cells that form a barrier called the epithelium. The cells at the top of the epithelium are called foveolar cells and they protect the stomach from the strong acid used to break down food. Underneath the surface epithelium is a thin layer of tissue called the lamina propria which supports the surface cells. Together, the surface epithelium and lamina propria are called the mucosa.
The most common symptoms of chronic gastritis are abdominal pain (aching or burning) that is worse when the stomach is empty, nausea, bloating, and loss of appetite.
The most common cause of chronic gastritis is an infection of the stomach with a bacteria called Helicobacter pylori. Infection is more common in rural areas and in developing parts of the world. Chronic gastritis can also be seen in people who have previously been treated for Helicobacter pylori. Chronic gastritis may persist for months or even years after successful treatment.
Other causes of chronic gastritis include:
The diagnosis is usually made after a small sample of tissue is removed in a procedure called a biopsy. The tissue is then examined under a microscope by a pathologist. Your pathologist may order additional tests such as immunohistochemistry or special stains to look for Helicobacter pylori.
Chronic gastritis means that your pathologist saw an increased number of specialized immune cells called plasma cells within the lamina propria. Pathologists describe this change as chronic inflammation.
Active gastritis means that in addition to chronic inflammation, your pathologist saw ongoing tissue injury or damage. Another term for active gastritis is acute gastritis. In order to make this diagnosis, your pathologist must-see specialized immune cells called neutrophils in the epithelium.
Active gastritis can be seen shortly after the injury or damage started or even later if you have not yet received treatment. The most common cause of active gastritis is infection with Helicobacter pylori. The neutrophils in the epithelium protect the body from bacteria but also damage the cells in the epithelium.
Active gastritis caused by Helicobacter pylori infection should be treated with antibiotics. If left untreated, Helicobacter infection can cause stomach ulcers. Untreated Helicobacter infection also increases the risk of developing cancer in the stomach.
Some pathology reports will describe chronic gastritis as chronic inactive gastritis. The addition of the word inactive in the diagnosis means that no specialized immune cells called neutrophils were seen damaging the epithelium. Neutrophils are typically seen shortly after the injury starts and are a sign of ongoing damage (see Active gastritis above).
Chronic gastritis that is not treated can damage the foveolar epithelium. If the damage continues for many years, a new type of epithelium similar to the epithelium normally found in the small intestine slowly replaces the foveolar epithelium.
The change from foveolar epithelium to small intestinal epithelium is an example of metaplasia and pathologists describe the specific type of metaplasia that takes place in the stomach as intestinal metaplasia. If your pathologist sees intestinal metaplasia in the tissue sample, it will be described in your report.
Intestinal metaplasia is a non-cancerous change that develops after many years of injury. While it in itself is not cancer, it increases the risk of developing a type of stomach cancer called adenocarcinoma over time. The risk is higher when another type of change called dysplasia is also seen (see Dysplasia below).
Most patients with chronic gastritis will not have dysplasia but when seen it will be described in your report. Pathologists divide dysplasia into low and high grades based on how abnormal the tissue looks when examined under the microscope.
Dysplasia is a non-cancerous change. However, it is considered a precancerous condition because it increases the risk of developing a type of stomach cancer called adenocarcinoma over time. The risk of cancer is higher with high-grade dysplasia.