Multicenter study of autoimmune gastritis in Japan: Clinical and endoscopic characteristics

Abstract

Background and Aim In Japan, the prevalence of autoimmune gastritis (AIG) is assumed to be very low. With the recent rapid decrease in Helicobacter pylori (Hp) prevalence, reports on AIG are increasing. This multicenter registry study aimed to clarify the characteristics of AIG, especially its endoscopic appearance. Methods A total of 245 patients with AIG from 11 institutions in Japan from January 2010 to October 2016 were included, and their clinical and endoscopic findings were evaluated. Results Mean age was 67.2 ± 11.4 years, and 63.7% of the participants were women. The most common approach to diagnose AIG was endoscopic examination. Repeated incorrect treatment for Hp infection, due to a false‐positive result in 13C‐urea breath test, ranked third among the basis for diagnosis of AIG. Associated gastric lesions were type 1 neuroendocrine tumor (11.4%), adenocarcinoma (9.8%), and hyperplastic polyps (21.1%). Corpus pan‐atrophy was the most common appearance (90.1%); however, remnant oxyntic mucosa was found in 31.5% of the patients (flat, localized type, 48.6%). Sticky adherent dense mucus and scattered minute whitish protrusions were also observed in approximately 30% of the patients. Despite the prevailing presumption of the antral mucosa remaining normal, 42.3% of the patients presented with various extents of atrophy, and patchy redness and circular wrinkle‐like patterns were both observed in approximately 20% of the patients. Conclusions The present study showed some prominent clinical characteristics and endoscopic findings of AIG. We believe that our study will facilitate the diagnosis of potential AIG.

Endoscopy opens the door to a new era of autoimmune gastritis research

“…Regarding the endoscopic characteristics of AIG, another new endoscopic finding of scattered minute whitish protrusions was proposed and is present in 32% of AIG cases . This mucosal finding was not reported in previous studies, so it may be specific to AIG.…”

“…Besides the well‐recognized corpus‐dominant atrophy including submucosal vessel visibility and flattened rugal folds, endoscopic appearance has not been evaluated in large AIG cohorts. One of the notable aspects of Terao's study is the evaluation of remnant oxyntic mucosa in the corpus. Not only the prevalence (70 cases, 31.5%) but also the endoscopic appearance of the oxyntic mucosa were investigated and categorized in detail.…”

“…Another impressive result is the endoscopic appearance of the antral mucosa of patients with AIG . Less than half of the cases had normal coloration (i.e.…”

“…Some have suggested the hygiene hypothesis—that is, improved sanitation and less exposure to microorganisms in childhood cause autoimmune and allergic conditions—may be applicable to AIG. As described, a decreased prevalence of H. pylori as well as the notion of a false‐positive urea breath test in AIG cases will increase the likelihood of suspecting AIG by endoscopy . However, there are several major concerns regarding AIG clinical practice in Japan.…”

“…Third, no follow‐up strategy for AIG has been established. Gastric cancer and neuroendocrine tumor are major associated lesions of AIG; therefore, surveillance for these lesions is required. In a follow‐up study of H. pylori gastritis, several risk factors for gastric cancer, such as intestinal metaplasia or open‐type endoscopic atrophy, were unveiled (although individual surveillance programs depending on risk factors have not been established).…”