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Colonoscopy plays an important role in reducing the incidence and mortality of colorectal cancer by detecting adenomas and other precancerous lesions. Image-enhanced endoscopy (IEE) increases lesion visibility by enhancing the microstructure, blood vessels, and mucosal surface color, resulting in the detection of colorectal lesions. In recent years, various IEE techniques have been used in clinical practice, each with its unique characteristics. Numerous studies have reported the effectiveness of IEE in the detection of colorectal lesions. IEEs can be divided into two broad categories according to the nature of the image: images constructed using narrow-band wavelength light, such as narrow-band imaging and blue laser imaging/blue light imaging, or color images based on white light, such as linked color imaging, texture and color enhancement imaging, and i-scan. Conversely, artificial intelligence (AI) systems, such as computer-aided diagnosis systems, have recently been developed to assist endoscopists in detecting colorectal lesions during colonoscopy. To gain a better understanding of the features of each IEE, this review presents the effectiveness of each type of IEE and their combination with AI for colorectal lesion detection by referencing the latest research data.

Abstract A 57‐year‐old woman with no significant medical history was referred after a colonoscopy for abdominal distension, which revealed a tumor in the lower rectum. Pre‐operative colonoscopy showed the tumor was 12 mm in size, located from the anorectal junction to beyond the dentate line, and was diagnosed as high‐grade intramucosal neoplasia or shallow submucosal invasive cancer. Endoscopic submucosal dissection was performed, and the lesion was resected en bloc. Pathological examination revealed moderately differentiated tubular adenocarcinoma with tubulovillous adenoma. The stratified squamous epithelium adjacent to the anal side of the lesion showed pagetoid spread of atypical cells with positive horizontal margins. We referred her to a surgeon for radical treatment. The mucosa surrounding the endoscopic submucosal dissection scar was normal on narrow‐band imaging magnification. We marked its oral side endoscopically as the resected boundary. Transanal local excision was performed. The horizontal margins were positive because atypical cells had spread into the stratified squamous epithelium of the anorectal side of the lesion. The patient was followed on an outpatient basis. Sixty days postoperatively, residual tumor growth was observed. The second local resection was performed after mapping biopsy. All resection margins were negative, there was no lymphovascular invasion. One year after surgery, no recurrence was observed. Regarding endoscopic findings, there are no reports of endoscopic findings of the rectal mucosa, or the squamous epithelium of the anus of pagetoid spread. Here, we report a review of perianal Paget's Disease that resulted in difficulties in borderline diagnosis of pagetoid spread, resulting in multiple therapeutic interventions.

Abstract We present the case of a 45‐year‐old man who underwent a screening total colonoscopy and developed delayed perforation after a cold snare polypectomy in the descending colon and sigmoid colon. The patient developed abdominal pain and was referred to our department for further evaluation and treatment. On clinical examination, we noted lower abdominal tenderness, mild rebound pain, and elevated levels of inflammatory markers. Abdominal contrast‐enhanced computed tomography confirmed the presence of free air in the abdomen. Since there were no signs of peritoneal inflammation and the vital signs were stable, we planned to perform endoscopic clip closure of the perforated area. The patient's symptoms improved with conservative management thereafter, including fasting, fluid replacement, and antibiotic administration. The patient was discharged on the 6th hospital day. In this case report, we discuss the usefulness of endoscopic clip closure in managing delayed perforation.

Abstract A 51‐year‐old woman visited our hospital with the chief complaint of tarry stools. Contrast‐enhanced abdominal computed tomography revealed leakage of contrast medium into the lumen of the small intestine. Subsequently, a double‐balloon endoscopy was performed, which revealed a submucosal mass‐like lesion in the jejunum. Although hemostasis was attempted with clips, complete hemostasis was difficult to achieve, and angiographic embolization was performed. Nevertheless, the anemia progressed, and a small bowel resection was performed. Histopathological examination led to a diagnosis of a ruptured submucosal aneurysm of the small intestine. Endoscopic hemostasis is often difficult to achieve for submucosal aneurysms in the intestine. The submucosal tumor‐like finding observed on endoscopy in submucosal aneurysms is termed an “SMT‐like sign” and is considered an important finding to diagnose aneurysms.

Abstract Objectives Previous studies of cold snare polypectomy (CSP) for sessile serrated lesions (SSLs) ≥10 mm were performed by experienced endoscopists, and therefore their skills might have significantly influenced results. In this study, we compared the efficacy and safety of CSP for SSLs ≥10 mm between experienced and trainee endoscopists. Methods In a 1:1 propensity score matched retrospective cohort study, we compared the complete resection rate, en‐bloc resection rate, adverse event rate, and procedure time between experienced and trainee groups. Thirteen endoscopists performed CSP, and we defined the experienced group as endoscopists with board certification from the Japan Gastroenterological Endoscopy Society. Results We examined 616 lesions with SSLs ≥10 mm resected by CSP between February 2018 and May 2022. We excluded 61 lesions from the analysis because they had simultaneously undergone hot snare polypectomy (n = 57) or had been taken over by experienced endoscopists from trainees in the CSP procedure (n = 4). Finally, we identified 217 propensity score‐matched pairs (n = 434). Between experienced and trainee groups, the results were complete resection rate (100 vs. 100%; p = 1.00), en‐bloc resection rate (73.2 vs. 75.6%; p = 0.24), adverse event rate (3.2 vs. 2.8%; p = 0.77), or procedure time (6.2 vs. 5.9 min; p = 0.64). Conclusions We have demonstrated the safety and efficacy of CSP for SSLs ≥10 mm performed by experienced and trainee endoscopists.

Abstract A 25‐year‐old man was referred to our center for investigation of a gastric submucosal tumor and an ulcer that had developed on its oral side. Endoscopic ultrasonography findings suggested the presence of an ectopic pancreas, and treatment with an oral proton pump inhibitor was planned for the ulcer. Over the subsequent 3 years, the patient endured recurring epigastric pain and episodes of passing black stools. Emergency endoscopy revealed that the morphology of the gastric submucosal tumor had transformed into a pedunculated polyp‐like morphology with a bleeding ulcer at the apex of the lesion. Endoscopic hemostasis using hemostatic forceps was performed. However, the patient continued to pass black stools. In light of the persistent symptoms and unique morphology of the lesion, endoscopic resection was attempted as a curative approach. The lesion was excised by hot snare polypectomy. Post‐treatment, the patient exhibited no signs of recurrence, marking a successful resolution. Three months later, a gastroduodenal endoscopy showed that the excised site had undergone scar formation without recurrence of the lesion. This case holds significant clinical value as it demonstrates the efficacy of a minimally invasive treatment strategy in managing repeated bleeding ulcerations of an ectopic pancreas, ultimately achieving a complete cure.

Background/Aims Diagnosis of Helicobacter pylori-naïve gastric cancer (HPNGC) is becoming increasingly important. This study aimed to explore the quality indicators for HPNGC detection. Methods We conducted a cross-sectional, nationwide, web-based survey of gastrointestinal endoscopists in Japan. In addition to questions about the number of HPNGC cases detected in a year and basic information, the questionnaire also consisted of 28 questions: (1) 18 about HPNGC awareness, (2) six about diagnostic proactiveness, and (3) four about interest in HPNGC. Results Valid responses were obtained from 712 endoscopists. The Japan Gastroenterological Endoscopy Society-certified endoscopists had a significantly higher HPNGC detection rate than the nonspecialists (0.42% vs. 0.32%, respectively; p=0.008). The results of the multiple regression analysis showed that Japan Gastroenterological Endoscopy Society certification and high awareness and interest scores were independent predictors of the HPNGC detection rate (p=0.012, p

Abstract Background Perigastric abscess caused by delayed perforation after endoscopic submucosal dissection is a very rare complication. In principle, delayed perforation after endoscopic submucosal dissection is treated surgically. Herein, we report a case of perigastric abscess caused by delayed perforation after gastric endoscopic submucosal dissection that was treated conservatively, without perforation closure, and in which the patient was discharged from hospital in a short period. Case presentation A-74-year-old Asian man was diagnosed with having early gastric cancer on follow-up endoscopy and was admitted to our hospital for endoscopic resection. Endoscopic submucosal dissection was performed without intraoperative complications. On postoperative day 2, the patient complained of a slight abdominal pain localized to the epigastric region and a small amount of melena. A computed tomography scan revealed the presence of free air in the peritoneal cavity, and a little fluid collection abutting the dorsal area of the stomach. An endoscopy examination showed a deep ulcer with the accumulation of pus, suggesting a perforation in the post-endoscopic submucosal dissection ulcer. We diagnosed a perigastric abscess, caused by delayed perforation after endoscopic submucosal dissection, and opted for conservative treatment, leaving the perforation site open to allow spontaneous drainage from the abscess into the stomach. A follow-up computed tomography scan revealed an encapsuled and localized perigastric abscess on postoperative day 5, and the disappearance of the free air and the regression of the perigastric abscess on postoperative day 7. A follow-up endoscopy examination on postoperative day 7 showed the closure of the perforation. Finally, surgery was avoided, and the patient was discharged on postoperative day 14, after a relatively short hospital stay. Conclusion Regarding the treatment of perigastric abscess, caused by delayed perforation after endoscopic submucosal dissection, leaving the perforation site open to allow spontaneous drainage may shorten the conservative treatment period.

Abstract Background Gastric mixed neuroendocrine–non-neuroendocrine neoplasms are rare malignant tumors. The lack of specific findings makes it difficult to diagnose endoscopically. We report the case of early gastric mixed neuroendocrine–non-neuroendocrine neoplasms treated by endoscopic submucosal dissection. Case presentation An 81-year-old Japanese female underwent esophagogastroduodenoscopy for screening and was treated with endoscopic submucosal dissection for the diagnosis of early gastric cancer. Histopathologically, the lesion was diagnosed as mixed neuroendocrine–non-neuroendocrine neoplasms (tubular adenocarcinoma 2 60%, endocrine cell carcinoma 40%), pT1b(submucosa (SM) 900 μm), pUL(−), Ly(+), v(−), pHM0, pVM0. After additional surgical resection without adjuvant chemotherapy, she has had no recurrences or metastases for 3 years. Conclusions Comparing narrow-band imaging magnified endoscopic findings with pathological findings, the depressed area with a lack of surface structure was consistent with the neuroendocrine cell carcinoma component, while narrow-band imaging magnification findings showed non-network vessels. In this case, we examined endoscopic findings of early stage mixed neuroendocrine—non-neuroendocrine neoplasms in detail and compared it with the pathological findings. We believe that these endoscopic findings contribute to the diagnosis of mixed neuroendocrine–non-neuroendocrine neoplasms and can lead to its early detection.

Abstract While duodenal neoplasms of the gastric phenotype are uncommon and their natural history is unknown, gastric neoplasms of gastric phenotype reportedly grow rapidly and can invade the submucosa. Several studies suggest that duodenal neoplasms of gastric phenotype might have a high risk of deep invasion and lymph node metastasis. Duodenal neoplasms of gastric phenotype might also have a high biological malignancy and likely require early treatment if detected. Here, we report two cases of intramucosal duodenal carcinoma with a gastric phenotype that grew rapidly but was successfully resected endoscopically.

Background and study aims Endoscopic submucosal dissection (ESD) of pharyngeal cancers with conventional endoscopes often is difficult, not only because of the narrow working space, but also because endoscope maneuverability in the pharynx is poor due to interference from the endotracheal tube and/or hyoid bone. However, we hypothesized that those problems could possibly be resolved by use of an ultrathin endoscope for ESD of superficial pharyngeal cancer. The aim of this prospective interventional study was to investigate the feasibility of ESD for superficial pharyngeal cancer using an ultrathin endoscope. Patients and methods This feasibility study was conducted at NTT Medical Center Tokyo between June 2020 and September 2021, and data from a total of 20 consecutively superficial pharyngeal cancers were analyzed. The primary outcome measure was the R0 resection rate. The ESD completion rate, en bloc resection rate, procedure time, and frequency of intraoperative and postoperative adverse events (AEs) were also evaluated as secondary outcome measures. Results Data from 16 patients with 20 lesions were included in the analysis. All of the lesions were successfully resected by ultrathin endoscope ESD, and the en bloc and R0 resection rates were 100 % and 85.0 % (17/20), respectively; the procedure time was 37.8 ± 28.2 minutes. No intraoperative or postoperative AEs were encountered in any cases. Conclusions ESD using an ultrathin endoscope is feasible for superficial pharyngeal cancers and has potential to be a safe and effective treatment option for these cancers.

Abstract Background and Aim With the increasing prevalence of persons without Helicobacter pylori (HP) infection, cases of HP‐negative gastric cancer are increasing. Although rare, cases of differentiated adenocarcinoma of the antrum have been reported in HP‐negative patients. We collected cases with such lesions and investigated their endoscopic and histological features. Methods Of 1965 consecutive patients with early gastric cancer who underwent endoscopic resection between January 2009 and December 2017, we extracted 9 cases of HP‐negative differentiated adenocarcinoma located in the antrum (HPN‐DAA). The clinical data, endoscopic findings, and histopathological findings were reviewed. Results Of the nine patients with HPN‐DAA, seven were male, and the median age was 53.8 years. The tumor arose from the pyloric gland mucosa in all cases. According to the endoscopic findings, the lesions were flat‐elevated or depressed, mimicking varioliform gastritis. Magnifying endoscopy with narrow‐band imaging showed the absence of a clear demarcation line or an irregular microvessel/surface pattern. As for the histopathological findings, eight of the nine lesions were diagnosed as high‐grade dysplasia/intraepithelial neoplasia, while the remaining case was diagnosed as tubular adenocarcinoma with submucosal infiltration. The findings of immunohistochemistry confirmed that three cases were of the intestinal mucin phenotype and six were of the mixed gastric and intestinal mucin phenotype. Conclusion HPN‐DAA is a very rarely occurring cancer that had never been recognized earlier. They belong to the new category of HP‐negative cancers, and there seems to be a certain number of such cases.

Abstract Endoscopic submucosal dissection (ESD) is the standard endoscopic treatment for early esophageal cancer. Esophageal stricture often occurs at the site of ESD for large lesions. When treating a metachronous lesion appearing at the severe stricture, it may be difficult to negotiate a conventional endoscope through the stricture. Using a thin endoscope may be a useful strategy for such lesions, though ESD using a thin endoscope is challenging because of poor maneuverability. Herein, we report a case of successful ESD for early esophageal cancer at the severe stricture, using a conventional endoscope. A 72‐year‐old man with a previous history of ESD for esophageal cancer and a post‐ESD esophageal stricture was referred to our hospital for metachronous early esophageal cancer. The lesion, 10 mm in diameter, was located at the stricture with a slight distal extension. Conventional endoscopes could not be negotiated through stricture. Therefore, submucosal dissection was performed from the oral to the anal aspect of the lesion, as far as possible. After completion of submucosal dissection of the oral aspect of the lesion and part of the lesion located on the stricture, the severe stricture was released, allowing the passage of conventional endoscope, and ESD of the entire lesion was completed en bloc. Histopathological examination showed squamous cell carcinoma, pT1a‐LPM. Stricture due to scarring may occur during the regeneration process of the defective mucosa, muscularis mucosa, and submucosal layer. Therefore, incision and dissection of the contracted mucosa, mucularis mucosa, and submucosal layer would release the stenosis.

Endoscopic submucosal dissection (ESD) for extensive esophageal cancer inevitably causes a post‐ESD stricture. It may be difficult to perform additional ESD if a new lesion develops on the anus side of the post‐ESD stricture. We sometimes perform balloon dilation of post‐ESD stricture in advance, so we could perform ESD using a transoral scope; however, there is a risk of balloon dilation causing severe tearing of the lesions if it is located near the stricture. A 68‐year‐old man who had undergone ESD for esophageal cancer several times was diagnosed with early esophageal cancer. The lesion was located near the anus side of the post‐ESD stricture. Unfortunately, the lesion was located on another post‐ESD scar. Although ESD using a transnasal scope was a useful option, it was expected to be challenging as the submucosal layer was thought to have severe fibrosis. We attempted to perform ESD with a transoral endoscope after stepwise scope bougienage of post‐ESD stricture.

Background and study aims Endoscopic submucosal dissection (ESD) has become the standard treatment for colorectal ESD, but large colorectal tumors remain difficult to remove. We developed a new method, called the palisade technique, by modifying the multiple tunneling technique. In this method, a palisade of submucosal tissue is left beneath the tumor to anchor a dissected specimen, maintaining effective submucosal traction. Patients and methods The study included 11 patients with large colorectal tumors that were over half the circumference of the colorectal lumen which were treated using the palisade technique from August 2017 to October 2019. Overall resection outcomes were assessed. Results All 11 lesions were removed en bloc. The R0 resection rate was 45.6 % because of marginal burning of the specimen, but no local recurrence was found after a median observation period of 31 months. The median submucosal dissection time (SDT) and submucosal dissection speed (SDS) were 170 minutes and 23.1 mm2/min, respectively. One case of post-ESD hemorrhage was successfully managed endoscopically, and two cases of post-colorectal ESD coagulation syndrome were managed conservatively. Conclusion The palisade technique can be an effective and safe technique for treating large colorectal tumors that extend over half the luminal circumference.

Since colorectal endoscopic submucosal dissection (ESD) remains technically difficult, hybrid ESD was developed as an alternative therapeutic option to achieve en bloc resection of relatively large lesions. In this feasibility study, we evaluated the safety and efficacy of hybrid colorectal ESD using a newly developed multifunctional snare. From June to August 2016, we prospectively enrolled 10 consecutive patients with non-pedunculated intramucosal colorectal tumors 20 – 30 mm in diameter. All of the hybrid ESD steps were performed using the “SOUTEN” snare. The knob-shaped tip attached to the loop top helps to stabilize the needle-knife, making it less likely to slip during circumferential incision and enables partial submucosal dissection. All of the lesions were curatively resected by hybrid ESD, with a short mean procedure time (16.1 ± 4.8 minutes). The mean diameters of the resected specimens and tumors were 30.5 ± 4.9 and 26.0 ± 3.5 mm, respectively. No perforations occurred, while delayed bleeding occurred in 1 patient. In conclusion, hybrid ESD using a multifunctional snare enables easy, safe, and cost-effective resection of relatively large colorectal tumors to be achieved. Study registration: UMIN000022545

Background and study aims: Recently, laparoscopic and/or endoscopic full-thickness resection (FTR) has been reported to be a useful technique for the treatment of superficial duodenal neoplasms (SDNs). In the current study, we evaluated clinical outcomes in 5 consecutive patients who underwent resection of nonampullary SDNs using laparoscopy-assisted endoscopic full-thickness resection with ligation Device (LAEFTR-L), which is an alternative FTR method developed to avoid peritoneal dissemination. Using a snare technique with a ligation band, the duodenal lesions were easily resected. The provisional and additional sutures for the resected site prevented delayed perforation and bleeding and they also protected the abdominal cavity from direct exposure to malignant cells. Complete resection could be achieved and FTR was histologically confirmed in all cases. The mean operation time was 173 minutes (range 138 – 217 minutes). Mean diameter of the resected specimen was 24 mm (range 18 – 32 mm). No adverse events (AEs) were observed. LAEFTR-L, which can achieve complete resection of nonampullary SDNs without severe AEs and peritoneal dissemination, could be a useful technique for the treatment of such lesions.

Background and study aims: Despite the clinical advantages of colorectal endoscopic submucosal dissection (ESD), an effective training system, especially for Western endoscopists, has been challenging to establish. Herein, we propose a novel training program using ex vivo animal models and evaluate the learning curve of colorectal ESD trainees without gastric ESD experience. Patients and methods: A total of 80 colorectal lesions were prospectively collected and removed by two novice operators. Before human ESD procedures, they received ESD training using an ex vivo porcine “proximal colon” model, which simulates a lumen with many folds and flexions. To assess the validity of our training system, the self-completion and en bloc R0 resection rates, the operation time, and prevalence of complications were compared between the first and latter period. Moreover the factors associated with prolonged operation time were evaluated. Results: The overall rates of self-completion and en bloc R0 resection were 98 % (78/80) and 100 % (80/80), respectively. The operation time during the first period was significantly longer than that during the latter period (86 ± 50 minutes vs. 60 ± 36 minutes, P = 0.01). Regarding complications, only two cases of perforations and delayed hemorrhage were observed during the first period; however, all of the complications were successfully managed endoscopically. The presence of fibrosis was identified as a significant independent predictor of a prolonged operation time during the first period (coefficient, 5.90; 95 %CI, 2.36 – 9.44, P = 0.002). Conclusions: Our trainees achieved high rates of self-completion and R0 resection without severe complications even during the first 20 cases, suggesting that our training programs using ex vivo animal models are useful for trainees without gastric ESD experience. Study registration: UMIN000013566

Esophageal endoscopic submucosal dissection (ESD) is technically difficult. To make it safer, we developed a novel method using overtube with a traction forceps (OTF) for countertraction during submucosal dissection. We conducted an ex vivo animal study and compared the clinical outcomes between OTF-ESD and conventional method (C-ESD). A total of 32 esophageal ESD procedures were performed by four beginner and expert endoscopists. After circumferential mucosal incision for the target lesion, structured as the isolated pig esophagus 3 cm long, either C-ESD or OTF-ESD was randomly selected for submucosal dissection. All the ESD procedures were completed as en bloc resections, while perforation only occurred in a beginner’s C-ESD procedure. The dissection time for OTF-ESD was significantly shorter than that for C-ESD for both the beginner and expert endoscopists (22.8±8.3 min versus 7.8±4.5 min, P

Background. Superficial duodenal neoplasms (SDNs) are a challenging target in the digestive tract. Surgical resection is invasive, and it is difficult to determine the site and extent of the lesion from outside the intestine and resect it locally. Endoscopic submucosal dissection (ESD) has scarcely been utilized in the treatment of duodenal tumors because of technical difficulties and possible delayed perforation due to the action of digestive juices. Thus, no standard treatments for SDNs have been established. To challenge this issue, we elaborated endoscopy-assisted laparoscopic full-thickness resection (EALFTR) and analyzed its feasibility and safety. Methods. Twenty-four SDNs in 22 consecutive patients treated by EALFTR between January 2011 and July 2012 were analyzed retrospectively. Results. All lesions were removed en bloc. The lateral and vertical margins of the specimens were negative for tumor cells in all cases. The mean sizes of the resected specimens and lesions were 28.9 mm (SD ± 10.5) and 13.3 mm (SD ± 11.6), respectively. The mean operation time and intraoperative estimated blood loss were 133 min (SD ± 45.2) and 16 ml (SD ± 21.1), respectively. Anastomotic leakage occurred in three patients (13.6%) postoperatively, but all were minor leakage and recovered conservatively. Anastomotic stenosis or bleeding did not occur. Conclusions. EALFTR can be a safe and minimally invasive treatment option for SDNs. However, the number of cases in this study was small, and further accumulations of cases and investigation are necessary.

Background/Aims: Diagnosis of Helicobacter pylori-naïve gastric cancer (HPNGC) is becoming increasingly important. This study aimed to explore the quality indicators for HPNGC detection. Methods: We conducted a cross-sectional, nationwide, web-based survey of gastrointestinal endoscopists in Japan. In addition to questions about the number of HPNGC cases detected in a year and basic information, the questionnaire also consisted of 28 questions: (1) 18 about HPNGC awareness, (2) six about diagnostic proactiveness, and (3) four about interest in HPNGC. Results: Valid responses were obtained from 712 endoscopists. The Japan Gastroenterological Endoscopy Society-certified endoscopists had a significantly higher HPNGC detection rate than the nonspecialists (0.42% vs. 0.32%, respectively; p=0.008). The results of the multiple regression analysis showed that Japan Gastroenterological Endoscopy Society certification and high awareness and interest scores were independent predictors of the HPNGC detection rate (p=0.012, p<0.001, p=0.024, respectively). Principal component analysis showed that the endoscopists who attended conferences for collecting information on HPNGC had a higher level of awareness. Conclusions: To improve the detection of HPNGC, it is necessary to increase the awareness of the disease. It is hoped that relevant societies will play an important role in endoscopists' education. [ABSTRACT FROM AUTHOR]