Multiple white flat lesions in the gastric corpus are not intestinal metaplasia

We read with interest the article by Pimentel-Nunes et al. [1] regarding narrow-band imaging in the diagnosis of premalignant gastric conditions and lesions. The diagnosis of gastric intestinal metaplasia (IM) is clinically important in terms of identifying patients who are at risk of developing gastric cancer. The most accurate currently accepted diagnostic method for gastric IM is histological examination. However, biopsy diagnosis has the potential limitation of sampling error because IM often shows patchy distribution in the gastric mucosa. Therefore, endoscopic diagnosis of IM would increase the accuracy of targeted biopsy. Moreover, if the endoscopic diagnosis were sufficiently accurate, the endoscopic findings themselves could be used to assess gastric cancer risk. We think this concept, endoscopic diagnosis of high risk mucosal conditions, is useful for risk stratification because it can change the approach to the endoscopic procedure (i. e. intensive observation for high risk patients during endoscopy) and can determine surveillance strategy immediately after endoscopy [2].

We would like to comment on an endoscopic image labelled Fig. 1e in the original article. In this image, a whitish patch with villiform structure is presented as “intestinal metaplasia in corpus.” Such lesions have recently been reported as an independent clinical entity by Japanese endoscopists [3]. These lesions were seen predominantly in women and were distributed in multiple locations in the upper corpus. Endoscopic gastric mucosal atrophy was observed in 31 % of the patients (4/13) but the remainder did not have gastric mucosal atrophy associated with Helicobacter pylori infection. All of the patients reported long-term use of a proton pump inhibitor (median 3.7 years). Histological examination of these lesions revealed hyperplastic changes in the foveolar epithelium with normal fundic glands, characteristics that are different from IM ([Fig. 1]).

Fig. 1 Example of a flat white lesion from the gastric corpus: a appearance on narrow-band imaging; b with magnification, c histological appearance.

Points for the differential diagnosis from IM are: (i) the appearance of whitish elevated patches in the upper corpus on white-light imaging (IM in the antrum is often represented by whitish elevated patches, whereas IM in the corpus is usually flat); and (ii) an apparently papillary or ridged surface structure without the light-blue crest sign [4] on magnified narrow-band imaging.

Although the actual clinical and pathological characteristics of this lesion need to be explored further, we would like to emphasize that this lesion can be seen in patients with neither atrophy nor IM who have little risk of developing gastric cancer. If this lesion is misdiagnosed as IM in such patients, they may be misclassified as high risk, therefore being subjected to unnecessary intensive surveillance endoscopy. In this respect, it is important to differentiate this lesion from gastric IM.

• References

• 1 Pimentel-Nunes P, Libânio D, Lage J. et al. A multicenter prospective study of the real-time use of narrow-band imaging in the diagnosis of premalignant gastric conditions and lesions. Endoscopy 2016; 48: 723-730
• 2 Lage J, Uedo N, Dinis-Ribeiro M. et al. Surveillance of patients with gastric precancerous conditions. Best Pract Res Clin Gastroenterol 2016; 30: 913-922
• 3 Yamaoka R, Kojima T, Yao K. et al. Novel endoscopic findings of multiple white flat lesions: A subtype of hyperplastic polyps in the stomach. United European Gastroenterol J 2016; (Suppl. 03) A386
• 4 Uedo N, Ishihara R, Iishi H. et al. A new method of diagnosing gastric intestinal metaplasia: narrow-band imaging with magnifying endoscopy. Endoscopy 2006; 38: 819-824