Intestinal metaplasia in gastric malignancy

OBJECTIVES Intestinal metaplasia is associated with gastric carcinomas, in particular intestinal-type carcinomas. According to the literature, intestinal metaplasia, especially the sulphomucin-rich incomplete type (type IIb or III) can be considered as a precancerous lesion. Intestinal metaplasia is not uncommon in gastric lymphomas, and the purpose of this study was to determine its prevalence and extent, its different subtypes and the distribution of sulphomucin and to compare these findings with those in gastric carcinomas. DESIGN The prevalence and grade of intestinal metaplasia were investigated in surgical specimens from 160 patients with gastric carcinoma (102) [intestinal type (69), diffuse type (33)] and gastric lymphoma (58) [marginal zone cell (29), diffuse large cell (29)]. Intestinal metaplasia is analysed by specific mucin stains. METHODS Intestinal metaplasia was described according to the Updated Sydney system. Using periodic acid-Schiff Alcian Blue pH 2.5 and high iron-diamine/Alcian Blue staining, the intestinal metaplasia was classified (Jass classification) and its sulphomucin content was determined. RESULTS The prevalence and extent of intestinal metaplasia are significantly higher in intestinal-type carcinomas than all other gastric malignancies. Subtyping of intestinal metaplasia is independent of the different types of gastric neoplasia. High sulphomucin positivity in the metaplastic epithelium is only seen in intestinal-type carcinomas, although in a small number of cases (21.5%). CONCLUSION Prevalence, extent and sulphomucin content of intestinal metaplasia are significantly higher in intestinal-type gastric carcinoma compared to diffuse-type carcinoma, marginal zone cell and diffuse large cell lymphomas in the stomach.