The endoscopic diagnosis of gastric mucosal lesions comprises two steps: detection and then characterization. After an endoscopic diagnosis has been made, endoscopists insist on taking at least one forceps biopsy from the target lesion to allow histological confirmation, because the diagnostic accuracy of endoscopy using conventional white-light imaging (C-WLI) alone is not sufficient [1]. As so rightly pointed out in this month’s issue of Gastric Cancer [1], we frequently encounter inconsistencies between the histological findings from biopsy specimens and endoscopically resected specimens. For example, the biopsy-based histological findings are of low-grade adenoma (LGA), but the resection-based histological findings are of high-grade adenoma (HGA) or early cancer (EC). This is because it is sometimes difficult for the pathologist to achieve a correct diagnosis from a small biopsy specimen alone, and it is impossible for the endoscopist to consistently obtain a target biopsy from the most suspicious part of the lesion referring to C-WLI endoscopy alone. Differentiating between LGA and HGA/EC is therefore difficult, even after histological biopsy-based examination. This can result in the overtreatment of lesions which are in fact LGAs. Dr. Kazuhiro Miwa’s clinical question is pertinent. Guidelines for the endoscopic treatment of LGA on biopsy have not been established, and a solution to this problem is clinically relevant. The development of narrow-band imaging (NBI) has enabled endoscopic optical biopsies throughout the gastrointestinal tract [2, 3]. However, NBI is not suited to lesion detection within the stomach because it is too dark to obtain an overview of the gastric mucosa due to the wide lumen of the stomach. On the other hand, magnifying narrow-band imaging (M-NBI) is a powerful tool for characterizing the gastric mucosal surface, because it can visualize the precise microanatomies of both the microvascular (MV) and microsurface (MS) patterns of gastric mucosal lesions (Table 1) [4]. Based on these visualized microanatomies, a VS (vessel plus surface) classification system has been proposed for differentiating between cancerous and noncancerous lesions [4]. The diagnostic system for ME was initially based upon the MV pattern alone [5]. In brief, the magnified endoscopic findings of early gastric cancer are (1) the presence of a demarcation line between a lesion and the background mucosa, and (2) the presence of an irregular MV pattern within the lesion [6]. Setting the criteria for cancer as the presence of both ME findings, we previously reported that ME is useful for differentiating between cancerous and noncancerous lesions that are small, flat, or depressed [7]. After incorporating NBI into ME, based on the MV pattern alone, we also reported previously that the sensitivity and the specificity of M-NBI were as high as 95.0 and 96.5%, respectively, for small depressed mucosal lesions when we applied M-NBI after inspection under C-WLI [8]. Let us consider why determination of the MS pattern should be mandatory, even after we have demonstrated that the MV pattern alone is useful for characterizing flat or depressed gastric mucosal lesions by ME. The answer is that we sometimes encounter difficulties in visualizing the subepithelial MV architecture in cases of elevated-type epithelial neoplasia [9]. Accordingly, we established a comprehensive diagnostic system—the VS classification system—involving both the MV and MS patterns, in order to facilitate the diagnosis of neoplasias of all macroscopic K. Yao (&) Department of Endoscopy, Fukuoka University Chikushi Hospital, 1-1-1 Zokumyoin, Chikushino, Fukuoka 818-8502, Japan e-mail: yao@fukuoka-u.ac.jp
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Apr 22, 2016
Manabu Muto + 6
Open Access
