Diagnosis: gastric intestinal metaplasia - what to do next?

Abstract

Purpose of review: One of the most vexing problems for gastroenterologists is what actions to take after receiving a histological diagnosis of gastric intestinal metaplasia. We approach the problem by starting with suggesting a biopsy protocol that ensures obtaining the biopsies required for diagnosis, assessing the status of the gastric mucosa, and effective communication with the pathologist and patient.

Recent findings: The rediscovery and integration of the long history of gastric damage and repair resulting in pseudopyloric metaplasia (called SPEM) into the thinking of investigators working with animal models of gastric cancer has resulted in improved ability to separate changes associated with benign repair from those associated with inflammation-associated gastric carcinogenesis.

Summary: Gastric intestinal metaplasia is a potential reversible product of injury and repair and not directly connected with carcinogenesis. Intestinal metaplasia is a biomarker for prior gastric injury and repair. The risk of gastric cancer is best assessed in relation to the severity, extent, and, most importantly, the cause of the atrophic changes.

FIGURE 1.

Correa cascades from 1975 and updated version from 1992. The term ‘small intestinal metaplasia’ is used as a synonym for ‘complete type’ or ‘type II’ intestinal metaplasia; ‘colonic metaplasia’ indicates ‘incomplete type’ or ‘type III’ intestinal metaplasia.

FIGURE 2.

Biopsy sample obtained from antral-appearing oxyntic mucosa. Intestinalized glands coexist with extensive pseudopyloric metaplasia (SPEM). The latter is stained brown by the TFF2 immunohistochemical stain, which stain both SPEM and superficial epithelia. Intestinalized glands do not show a TFF2-positive immunoreaction (a: H&E, original magnification 10×; (b) TFF2 immunohistochemical staining; original magnification 5×).

FIGURE 3.

Helicobacter pylori-associated gastric cancer is an inflammation associated cancer in which genetic instability is exaggerated by H. pylori and environmental factors. Metaplastic gastric epithelium (pseudopyloric and intestinal) reflects mucosal damage independent of whether is or is not associated with a gastric cancer risk. In H. pylori infection, it is best considered as a biomarker of potential cancer risk. Adapted with permission from [^■].

FIGURE 4.

These two images illustrate the concept of focal (panel a where only one foveola is affected) versus diffuse (panel b where the entire mucosa is intestinalized) metaplasia. However, one must interpret these designations with skepticism, as the true extent of intestinal metaplasia in a stomach can never be assessed accurately by biopsy sampling. Careful gastric biopsy mapping, however, allows pathologists to make reasonable estimates.

FIGURE 5.

Illustration showing the Sydney system biopsy sites and the use of separate bottles for the antral and corpus specimens.

FIGURE 6.

Endoscopic picture looking from the proximal to the distal stomach in a patient with extensive atrophy extending along the lesser cure. Biopsy of the atrophic lesser curve corpus likely shows pseudopyloric metaplasia whereas the greater curve biopsy would be nonatrophic. Placing all five biopsies in one bottle would likely confuse the pathologist. If in separate bottles, the pathologist could determine that the patient had extensive antral and lesser curve corpus atrophy.

FIGURE 7.

Illustration of the importance of using large forceps. The sequence (a), (b), and (c) illustrates the relative biopsy size, tissue specimen, and tissue section with a large forceps contrasted with sequence (d), (e), and (f) in which a small forceps is used. A larger specimen (as in c) also allows a better orientation and, consequently, a better interpretation than can be made by examining the disorderly fragments of mucosa depicted in panel f.

FIGURE 8.

The Operative Link for Gastritis Assessment of Atrophic Gastritis system of staging risk for developing gastric cancer. Atrophy scores from antral and corpus specimens are plotted on the table to reach a stage. For example, a set of biopsies with a score of 2 in the antrum and 3 in the corpus will have an OLGA Stage IV. Adapted with permission from [40]. OLGA, the Operative Link for Gastritis Assessment of Atrophic Gastritis.