MWEL and CLM are characteristic endoscopic features in PPI users. A gender-associated difference was noted in terms of the frequency of these lesions.

Background/Aims: Dual red imaging (DRI) is a new, image-enhanced endoscopy technique. There are few reports about the usefulness of DRI during gastric endoscopic submucosal dissection (ESD). We aimed to examine the usefulness of DRI in endoscopic hemostasis during gastric ESD. Methods:We enrolled a total of 20 consecutive patients who underwent gastric ESD. Five endoscopists compared DRI with white light imaging (WLI) for the visibility of blood vessels and bleeding points while performing endoscopic hemostasis. Results: The visibility of blood vessels was increased in 56% (19/34) of the cases, and the visibility of bleeding points was improved in 55% (11/20) of the cases with the use of DRI compared with the use of WLI. Conclusions: DRI improved the visibility of blood vessels and bleeding points in cases with oozing bleeding, blood pooling around the bleeding points, and multiple bleeding points. Clin Endosc 2020;53:54-59

Background and aim Endoscopic ultrasonography is a reliable diagnostic modality for determining indications of endoscopic submucosal dissection for early gastric cancer. We aimed to clarify the clinical significance of endoscopic ultrasonography in the invasion depth diagnosis of early gastric cancer. Methods We retrospectively assessed 1598 consecutive patients with 2001 early gastric cancers who underwent EUS before ESD or surgery between October 2010 and April 2019 at our institution. Lesions were classified according to endoscopic ultrasonography-determined invasion depth as EUS-M/SM1 (lesions confined to sonographic layers 1 and 2 or lesions with changes in sonographic layer 3; depth, < 1 mm) and EUS-SM2 (lesions with changes in sonographic layer 3; depth, ≥ 1 mm). We evaluated the invasion depth determination accuracy of endoscopic ultrasonography and analyzed the clinicopathological features of misdiagnosed early gastric cancer cases. Results The invasion depth determination accuracy was as follows: EUS-M/SM1: pathological T1a/T1b1 early gastric cancer, 97%; EUS-SM2: pathological T1b2 early gastric cancer, 79%. The accuracy, sensitivity, specificity, positive predictive value, and negative predictive value were 95%, 98%, 69%, 97%, and 79%, respectively. In EUS-M/SM1 early gastric cancer, tumor size of ≥ 15 mm, presence of ulceration, and undifferentiated histological type were significantly associated with endoscopic ultrasonography accuracy. In EUS-SM2 early gastric cancer, tumor size of ≥ 30 mm was significantly associated with endoscopic ultrasonography accuracy. Conclusions Endoscopic ultrasonography is a useful modality in accurately determining the invasion depth of early gastric cancer before endoscopic submucosal dissection.

Background and Aim: Reddish depressed lesions (RDLs) frequently observed in patients following Helicobacter pylori eradication are indistinguishable from gastric cancer. We examined the clinical and histological feature of RDLs and its relevant endoscopic diagnosis including magnifying narrow-band imaging (M-NBI). Methods: We enrolled 301 consecutive patients with H. pylori eradication who underwent endoscopy using white light imaging (WLI). We examined the prevalence and host factors contributing to the presence of RDLs. Next, we used M-NBI in 90 patients (104 RDLs), and compared the diagnostic efficacy between M-NBI and WLI groups using propensity-score matching analysis. Results: In 301 patients after eradication, 117 (39%) showed RDLs. Male, open-type atrophy, and gastric cancer history were risk factors for RDLs. A gastric biopsy was needed in 83 (71%) during WLI observation and only 2 were diagnosed with adenocarcinoma. In M-NBI group, a biopsy was performed in 21 (20%), and 9 were diagnosed with adenocarcinoma. A biopsy was required in fewer patients, and the positive predictive value of a biopsy was statistically higher in M-NBI than in the WLI group (p < 0.01). Conclusions: RDLs are frequently observed in high-risk patients for gastric cancer after eradication. M-NBI demonstrated significantly superior diagnostic efficacy with respect to RDL.

Background: Gastric cancer develops even in Helicobacter pylori(H. pylori)-uninfected patients and its typical histological feature is signet ring cell carcinoma (SRCC) within the mucosal layer. However, the biological characteristics of SRCC remain unclear. We aimed to clarify the pathological and genetic features of SRCC in H. pylori-uninfected patients. Methods: Seventeen H. pylori-uninfected patients with mucosal SRCCs were enrolled and their clinicopathological characteristics were compared with those of H. pylori-infected patients with mucosal SRCCs. Seven SRCCs without H. pylori-infected, including two invasive SRCCs, and seven H. pylori-infected SRCCs were subjected to a genetic analysis using next-generation sequencing. Results: H. pylori-uninfected patients with mucosal SRCCs revealed male dominancy and a significantly higher prevalence of smokers among them as compared with the H. pylori-infected patients with SRCC. A CDH1 mutation (frame shift indel) was detected in one H. pylori-uninfected cancer not only in the mucosal SRCC but also in the invasive portion. A TP53 mutation was detected in one SRCC without H. pylori-infected. In the control group, ARID1A and TP53 mutations were detected in one SRCC each. The C to A mutation, which is a characteristic smokinginduced mutation, was not found in any of the samples. Conclusions: Some SRCCs in H. pylori-uninfected patients may have a malignant potential similar to that of SRCCs in H. pylori-infected patients. Smoking may not be the main carcinogenic factor for the development of SRCCs among the H. pylori-uninfected patients.