ESD is an established minimally invasive treatment for superficial esophageal cancers. However, ESD for circumferential lesions, those at or around post-treatment scars, lesions coexisting with esophageal varices, and recurrent lesions after chemoradiotherapy (CRT) remains challenging. Although circumferential lesions are favorable candidates for ESD, postoperative strictures remain controversial. Lesions occurring in areas of scarred ulcers and those that recur after CRT are candidates for intractable ESD, with a high possibility of non-curative resection and complications. Furthermore, lesions complicated by esophageal varices are at risk of bleeding. Alternative endoscopic treatments for ESD, such as photodynamic therapy, argon plasma coagulation, and radiofrequency ablation, have recently drawn much attention in cases intractable to ESD with promising clinical efficacy.

Gastric mucosal changes associated with proton pump inhibitors (PPIs), including potassium-competitive acid blockers (P-CABs), were first described by Haruma as gastropathy associated with PPI (GAP). GAP involves the development and enlargement of fundic gland polyps and foveolar-hyperplastic polyps, multiple white and flat elevated lesions (Haruma-Kawaguchi lesions), cracked mucosa, cobblestone-like mucosa, and black spots. New gastric lesions such as white spots, diffuse redness, and web-like mucus have also been noted with the introduction of P-CABs in Japan in 2015,.

The mechanisms of GAP are unknown; however, hypergastrinemia secondary to PPI, P-CABs, or other factors may be involved. Additionally, an acid-free environment in the stomach, caused by the strong inhibitory effect of P-CAB on acid secretion, is a common finding in autoimmune gastritis. These occurrences must be noted, and the detailed pathogenesis and clinical importances of these cases must be examined, as the frequency of GAP is expected to increase in the future.

A 27-year-old woman visited the emergency department with a chief complaint of right lower abdominal pain. CT revealed an intussusception in the ascending colon, with no discernible tumor in the leading portion. Fluoroscopic-guided total colonoscopy revealed that the leading portion was formed by the edematous cecum, which was rapidly reduced by insufflation through an endoscope. No tumor was detected in the cecum, but the findings indicated colitis with reddish edematous mucosa accompanied by several erosions. Enterohemorrhagic Escherichia coli (EHEC) O-157 was detected in stool cultures obtained during colonoscopy; thus, the final diagnosis was EHEC colitis-induced intussusception. Endoscopic intervention enabled the reduction of intussusception and rapid diagnosis of colitis without a tumor.

An 82-year-old woman presented with severe lower abdominal pain. Physical examination revealed abdominal distension and tenderness. CT demonstrated dilation of the sigmoid colon, a whirl sign of the sigmoid mesocolon, pneumatosis intestinalis in the sigmoid colon, and a small amount of intraperitoneal free air. Given her stable general condition, absence of significant peritoneal irritation signs, and normal laboratory findings, the intraperitoneal free air was attributed to pneumatosis intestinalis rather than perforation secondary to sigmoid volvulus. Endoscopic detorsion was successfully performed, and the postoperative course was uneventful. However, 1.5 months later, the sigmoid volvulus recurred. Endoscopic detorsion was repeated, followed by laparoscopic sigmoidectomy to prevent further recurrence. Prolonged exposure to trichloroethylene in the workplace was considered a potential cause of the intestinal pneumatosis. This case highlights the clinical significance of recognizing that intraperitoneal free air can occur in patients with pneumatosis intestinalis without gastrointestinal perforation.

An eighty-six-year-old man was hospitalized with obstructive jaundice and cholangitis. An uncovered self-expandable metallic stent (USEMS) was placed to treat bile duct stenosis due to ampulla of Vater carcinoma.

Three days after USEMS placement, the patient developed severe nausea and vomiting. As no specific findings were noted on blood tests, abdominal imaging, or gastrointestinal endoscopy, we concluded that his symptoms were caused by the placement of the USEMS; thus, the decision was made to remove it.

We placed a fully covered self-expandable metallic stent (CSEMS) inside the USEMS using the stent-in-stent technique. Two weeks later, we attempted to remove both SEMSs but were unsuccessful.

Therefore, we performed large balloon dilation of the SEMSs and were able to safely remove both stents. Following stent removal, the patientʼs symptoms completely resolved.

Although we initially failed to remove the SEMSs using the stent-in-stent technique alone, successful removal was ultimately achieved by combining large-balloon dilatation with the stent-in-stent technique.

We conclude that this combined approach is a useful method for endoscopic removal of biliary USEMS.

The water pressure method (WPM) is a technique used to enter the submucosal layer during gastrointestinal endoscopy procedures, by utilizing the buoyancy and pressure of the endoscopeʼs water pumping function. It was developed to overcome a range of challenges related to difficult duodenal ESD procedures. Our group has been using WPM for various gastrointestinal ESDs, and recently reported favorable results regarding its usage for pharyngeal ESDs as well. Pharyngeal ESDs must be performed in collaboration with both otolaryngologists and anesthesiologists, considering the unique anatomy and potential complications associated with the region. Similarly, as with other gastrointestinal ESD procedures, WPM during pharyngeal ESD makes creating mucosal flaps easier so that the subepithelial layer can be penetrated and dissected. WPM has the potential to streamline strategies for pharyngeal ESD, making it particularly useful in this context.

With underwater ESD, halation is prevented, and the field of view is increased by approximately 1.3 times. Additionally, buoyancy can provide traction and improve maneuverability underwater after deaeration. However, bubble formation during dissection obstructs the field of view, and achieving hemostasis with saline immersion during intraoperative bleeding remains a challenge. To address this issue, we devised a method for creating turbulence within a tapered, side-hole-free hood (CAST hood;calibrated, small-caliber tip, transparent hood), which we named a gas-free immersion (GFI) system. In the GFI system, when the air/water valve button is pressed, fluid is directed solely to the endoscopic lens. This creates turbulence inside the CAST hood, and the bubbles generated can be expelled outside the hood. In addition, when bleeding occurs or when trying to maintain the field of view, applying pressure to the bleeding site on the wider side of the CAST hood is effective. Furthermore, when combined with a double-channel endoscope, rapid hemostasis can be achieved using hemostatic forceps inserted into one of the accessory channels. In this section, we introduce underwater ESD after deaeration using a GFI system with the aid of video images.

The consensus-based TOKYO criteria were proposed as a standardized reporting system for endoscopic transpapillary biliary drainage. The primary objective was to address issues arising from the inconsistent reporting of stent outcomes across studies, which has complicated the comparability and interpretation of study results. However, the original TOKYO criteria were not readily applicable to recent modalities of endoscopic biliary drainage such as biliary drainage based on endoscopic ultrasound or device-assisted endoscopy. There are increasing opportunities for managing hilar biliary obstruction and benign biliary strictures through endoscopic drainage. Biliary ablation has been introduced to manage benign and malignant biliary strictures. In addition, the prolonged survival times of cancer patients have increased the importance of evaluating overall outcomes during the period requiring endoscopic biliary drainage rather than solely focusing on the patency of the initial stent. Recognizing these unmet needs, a committee has been established within the Japan Gastroenterological Endoscopy Society to revise the TOKYO criteria for current clinical practice. The revised criteria propose not only common reporting items for endoscopic biliary drainage overall, but also items specific to various conditions and interventions. The term “stent-demanding time” has been defined to encompass the entire duration of endoscopic biliary drainage, during which the overall stent-related outcomes are evaluated. The revised TOKYO criteria 2024 are expected to facilitate the design and reporting of clinical studies, providing a goal-oriented approach to the evaluation of endoscopic biliary drainage.

In recent years, there have been concerns that Japanʼs endoscopic technology development and international standing have declined relative to those of two decades ago. Amid the transformation of global political and economic structures—namely, the changing international political and economic order—and the remarkable progress of related scientific fields, Western countries as well as emerging nations such as China and India have rapidly advanced in technological innovation, thereby enhancing their global presence. In this context, the author felt the need to objectively assess Japanʼs current position in endoscopy through international engagement. In 2024, the author interviewed 23 global opinion leaders in person at international conferences, asking them how they perceived the current state of Japanese endoscopic medicine and healthcare. Based on the insights obtained from these dialogues, this report also reflects on the present and future of the field of endoscopy in Japan.

These conversations with global leaders revealed their sharp and comprehensive viewpoints, clearly outlining Japanʼs expected role in the international community and the critical challenges that must be addressed. Overall, the interviewees consistently expressed high praise for Japanʼs advanced capabilities in early cancer diagnosis, sophisticated endoscopic therapeutic techniques such as ESD, and a meticulous and structured approach to education in endoscopy. These evaluations confirm that Japanese endoscopic medicine continues to lead globally. However, at the same time, every leader also pointed out common and pressing challenges: the need to strengthen collaborative frameworks (including international joint research), enhance communication skills, and disseminate findings in English. Additional issues include the importance of healthcare economics, sustaining international competitiveness, proactively adopting emerging technologies, and appropriately addressing a broader range of benign diseases. Although Japanʼs endoscopic technology remains at a high level, rapid progress on the global stage means that Japan cannot afford to fall behind. Strategic and sustained efforts are needed to maintain Japanʼs unique strengths while also responding effectively to international demands.