Artificial-intelligence-based computer-aided diagnosis (CAD) systems have developed remarkably in recent years. These systems can help increase the adenoma detection rate (ADR), an important quality indicator in colonoscopies. While there have been many still-image-based studies on the usefulness of CAD, few have reported on its usefulness using actual clinical videos. However, no studies have compared the CAD group and control groups using the exact same case videos. This study aimed to determine whether CAD or endoscopists were superior in identifying colorectal neoplastic lesions in videos. In this study, we examined 34 lesions from 21 cases. CAD performed better than four of the six endoscopists (three experts and three beginners), including all the beginners. The time to lesion detection with beginners and experts was 2.147 ± 1.118 s and 1.394 ± 0.805 s, respectively, with significant differences between beginners and experts (p < 0.001) and between beginners and CAD (both p < 0.001). The time to lesion detection was significantly shorter for experts and CAD than for beginners. No significant difference was found between experts and CAD (p = 1.000). CAD could be useful as a diagnostic support tool for beginners to bridge the experience gap with experts.

Although gastric mucosa-associated lymphoid tissue (MALT) lymphoma without Helicobacter pylori (HP) has increased recently, a specific endoscopic classification has not been established; its endoscopic characteristics have not been investigated. In this study, we retrospectively investigated gastric MALT lymphoma without HP in our hospital and assessed differences in the endoscopic findings according to HP infection status. Fifty-seven patients with gastric MALT lymphoma Lugano stage I, diagnosed between January 2013 and March 2023, were divided into three groups (currently HP infected, previously infected, and uninfected), wherein their endoscopic findings were evaluated. Furthermore, the superficial type, as per the classification of Sano et al., was independently subdivided based on the endoscopic differential diagnoses, as follows: atrophic gastritis-like, angiodysplasia-like, superficial gastritis-like, and undifferentiated carcinoma-like. Compared with the currently infected group, the HP-uninfected group tended to have more small lesions without erosion and more discolored, undifferentiated carcinoma-like depressed lesions. In addition, the positive rate of the tree-like appearance (TLA) and ballooning characteristics of gastric MALT lymphoma in magnified findings was lower in the HP-uninfected group. In patients without HP infection, MALT lymphoma should be excluded, even in the absence of suspicious magnifying findings such as TLA or ballooning.

Neuroendocrine tumors (NETs) are located primarily in the submucosal layer and require careful resection. Conventional endoscopic mucosal resection (EMR) has a risk of positive deep resection margins. En bloc resection is more feasible in endoscopic submucosal dissection (ESD); however, in the duodenum, there is a heightened risk of intraoperative or delayed perforation owing to the thin duodenal wall and effects of inflowing bile and pancreatic juices [1]. The use of an over-the-scope (OTS) clip during polypectomy can greatly reduce the perforation risk [2] and is reportedly safe for duodenal NETs [3]. However, its use during polypectomy to resect NETs located in the pocket of a duodenal ulcer scar has not been reported. We report the use of this method for the safe, rapid, en bloc resection of such tumors located in the anterior wall of the duodenal bulb ([Fig. 1], [Fig. 2], [Video 1]). Video 1 En bloc resection by polypectomy with over-the-scope clip for a neuroendocrine tumor located within a pocket created by duodenal ulcer scarring. In the duodenal mucosa and submucosa, even a tiny biopsy causes severe submucosal fibrosis, which may render snaring unfeasible [4]. The lesion in our patient had previously been biopsied and was located in a pocket created by duodenal ulcer scarring. Given the fibrotic interference and operative difficulty, regular EMR or ESD was considered unfeasible. As the lesion measured only 3 mm, an OTS clip could be used and could be positioned to just avoid the pyloric ring. OTS clip use during polypectomy involves a high cost, restrictions on lesion size, and the possibility of stenosis, depending on the location. However, it has the major advantages of greatly decreasing the perforation risk, shortening the operating time, and enabling the resection of the deep submucosal layer [3]. We thus considered OTS clip extremely useful for duodenal NETs that are in a position that makes their conventional endoscopic resection difficult. Endoscopy_UCTN_Code_TTT_1AO_2AG Article published online: 30 March 2023 © 2023. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/) Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, Germany