White flat lesions in the gastric corpus may be intestinal metaplasia

We read with great interest the comment from Uedo et al. stating that the image labelled Fig. 1e included in our manuscript [1] does not show intestinal metaplasia (IM). Instead, the authors claim that the image represents foveolar hyperplasia. They cite a series of cases presented only as a poster and show some images that they feel are similar to the one included in our article.

Our picture was taken from a 69-year-old Romanian woman with no long-term use of proton pump inhibitors (PPIs) who underwent endoscopy for surveillance of atrophic gastritis. Endoscopy showed several areas similar to our image dispersed through the mucosa ([Fig. 1]). Histology showed extensive IM in the corpus ( [Fig.2]). So, probably in this case the image does in fact represent IM.

Fig. 1 Narrow-band imaging (NBI) appearances of apparent intestinal metaplasia dispersed throughout the gastric body.

Fig. 2 Histological images of intestinal metaplasia in the gastric body.

Even though we respect the opinion of Uedo, we believe that it is impossible to be 100 % sure about the histological diagnosis of a lesion from just one image. No single narrow-band imaging (NBI) pattern offers 100 % accuracy for the diagnosis of gastric lesions [2]. Moreover, to our knowledge, the only NBI classification that is validated for the diagnosis of gastric lesions is the one that we described in 2012 (Western and Japanese gastroenterologists included) [3]. In our study, the B (ridge/tubule-villous) pattern presented a global accuracy of 84 % for the diagnosis of IM (80 % specificity). In the present study, the results were better with 92 % specificity [1]. We agree with Uedo et al. that the presence of light-blue crests (LBCs) increases specificity [3]. However, even with LBCs, the false-positive rate described by the author was 7 % (and not 0 %) [4].

Nevertheless, even in expert eyes, there will be a 5 % – 15 % rate of false positives and our opinion, based on our clinical practice and in accordance with the commentaries by Uedo, is that foveolar hyperplasia is an important cause of endoscopic misdiagnosis of IM. When we reviewed the last 100 biopsies performed in our institution for which we stated that there was IM using NBI, foveolar hyperplasia was the cause of a false-positive result in 7 out of 10 cases. Therefore, it is also our opinion that the presence of this NBI pattern may represent foveolar hyperplasia.

However, no single study has evaluated these appearances and both our and Uedo’s opinions can only be considered as, at most, expert opinion and not as rules. What we recommend is that NBI should be used to guide biopsies and not to replace histology, which is still the gold standard [5]. We suggest applying an endoscopic grading of IM (EGGIM) that has a strong correlation with histology, particularly in advanced cases of gastritis [1] [6]. Nevertheless, histology should always be taken into account to overcome the few but existent false-positive cases.

In conclusion, there is no endoscopic pattern that is 100 % accurate for the diagnosis of any lesion and, specifically, there is no single study comparing endoscopic NBI features for the distinction of IM from foveolar hyperplasia. In this particular case, it looks, contrarily to the opinion of Uedo et al., as if the image does indeed represent IM. For this reason, we do not think it is correct to say that “white flat lesions in the gastric corpus are not IM” since, in fact, they may be!

• References

• 1 Pimentel-Nunes P, Libanio 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 Kikuste I, Marques-Pereira R, Monteiro-Soares M. et al. Systematic review of the diagnosis of gastric premalignant conditions and neoplasia with high-resolution endoscopic technologies. Scand J Gastroenterol 2013; 48: 1108-1117
• 3 Pimentel-Nunes P, Dinis-Ribeiro M, Soares JB. et al. A multicenter validation of an endoscopic classification with narrow band imaging for gastric precancerous and cancerous lesions. Endoscopy 2012; 44: 236-246
• 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
• 5 Pimentel-Nunes P, Libanio D, Dinis-Ribeiro M. Evaluation and management of gastric superficial neoplastic lesions. GE Port J Gastroenterol 2017; 24: 8-21
• 6 Lage J, Pimentel-Nunes P, Figueiredo PC. et al. Light-NBI to identify high-risk phenotypes for gastric adenocarcinoma: do we still need biopsies?. Scand J Gastroenterol 2016; 51: 501-506