"Intestinal Metaplasia of the Gastric Mucosa" in the Gastroscopy Report Is One of the Precancerous Lesions of Gastric Cancer
More and more people now include gastroscopy in their health checkups, and some examination reports contain the phrase "intestinal metaplasia of the gastric mucosa." Many people cannot understand what this term means. Today I write to introduce the significance of intestinal metaplasia of the gastric mucosa.
The stomach is one of the digestive tubes of the digestive system and has the general structural features of a digestive tube. Except for the oral cavity and pharynx, the wall of a digestive tube is divided from inside to outside into four layers: the mucosa, submucosa, muscularis, and adventitia. The mucosal layer is composed of epithelium, lamina propria, and muscularis mucosae; the mucosal epithelium of different digestive tubes is composed of different types of epithelial tissue.
The normal gastric mucosa is originally covered by a single layer of columnar epithelial cells. Simple columnar epithelium is a layer of prism-shaped cells: viewed from the surface, the cells are hexagonal or polygonal; in a vertical section, the cells are columnar, hence the name simple columnar epithelial cells. This columnar epithelium has absorptive and secretory functions suited to the function of the stomach.
On gastric mucosa with intestinal metaplasia, cell types normally found in the intestinal mucosa appear, such as goblet cells. Goblet cells are shaped like goblets: narrow at the base and swollen at the top, filled with secretory granules, which are a kind of mucinogen. After the mucin in goblet cells is secreted, it combines with water to form mucus, which lubricates and protects the epithelium. It is a common cell type in the intestinal mucosal epithelium; if it appears in the gastric mucosa, it indicates that the gastric mucosa is no longer normal.
During development, the types of epithelial cells in each part of our body are fixed. If a cell type that should not be present appears somewhere (medicine calls these atypical cells), it means a gene mutation has occurred there. A gene mutation in somatic cells usually means canceration; therefore, when intestinal metaplasia appears in the gastric mucosa, the stomach has already entered a precancerous state, or even an early gastric-cancer state, and attention is required. When necessary, the area of intestinal metaplasia should be surgically resected, and the excised tissue examined pathologically to determine whether canceration has occurred.
According to the type of metaplastic cells, intestinal metaplasia of the gastric mucosa is divided into small-intestinal type and colonic type. Among them, small-intestinal-type intestinal metaplasia carries a lower canceration risk, while colonic-type intestinal metaplasia carries a higher canceration risk.
Intestinal metaplasia of the gastric mucosa is usually an adaptive change occurring after long-term stimulation of the gastric mucosa. Helicobacter pylori, chronic gastritis, bile reflux, gastric ulcers, and long-term consumption of pickled foods can all cause intestinal metaplasia. Some drugs may also cause intestinal metaplasia of the gastric mucosa; for example, long-term use of proton-pump inhibitors (antacids whose names end in "prazole," such as omeprazole and rabeprazole) may lead to intestinal metaplasia. Intestinal metaplasia may also be related to genetic factors. Patients with intestinal metaplasia whose first-degree relatives have a history of gastric cancer have a canceration risk more than five times higher than ordinary people.
Patients with the above chronic gastric diseases or a family history of related conditions should, after the age of 40, have a gastroscopy once a year or once every two years; when intestinal metaplasia of the gastric mucosa is found, it should be dealt with promptly. Usually, even if intestinal metaplasia of the gastric mucosa has become cancerous tissue, it is early gastric cancer, and the surgical radical cure rate is as high as over 90%.