The safety and efficacy of EUS-BD have markedly improved due to recent advancements in device design. This review highlights the structural characteristics and clinical significance of the Key devices used in EUS-BD—including puncture needles, guidewires, dilators, and stents—based on the latest literature. Notably, many of these innovative devices were developed in Japan, and their global adoption is expected to further enhance the technical outcomes of EUS-BD.

The incidence of reflux esophagitis is increasing in Japan along with a gradual rise in esophageal adenocarcinoma cases originating from Barrett’s esophagus, which is closely related to reflux esophagitis. The prognosis of advanced esophageal adenocarcinoma is poor, and early detection using endoscopy is necessary to improve patient prognosis. Our nationwide multicenter survey showed that the endoscopic features of superficial adenocarcinomas were mostly reddish and elevated （or protruded）. More than two-thirds were localized on the anterior to right-side wall, mainly at the 2° position （the triad of superficial cancer）. However, diagnosing early-stage cancers occurring in Barrett’s esophagus with chronic inflammation is challenging using white-light endoscopy alone. Since the 2000s, several advanced endoscopic imaging techniques have emerged, and many reports have demonstrated their utility in the early detection of Barrett’s esophageal adenocarcinoma. This review summarizes the previous reports on practically applicable advanced endoscopic diagnostic techniques in Japan, such as image-enhanced endoscopy （virtual chromoendoscopy） and acetic acid-enhanced endoscopy. These techniques have demonstrated high diagnostic performance and are recommended for use in combination with white-light endoscopy for the surveillance of Barrett’s esophagus in recent Western guidelines. Artificial intelligence-based diagnostic systems have also been developed in recent years, and their usefulness in detecting superficial adenocarcinomas and diagnosing their submucosal invasion has been reported; however, their applicability in general clinical practice remains unclear. We also discuss the differences between Japan and the West, including pathological diagnosis and the recently reported surveillance method based on the incidence of cancer development in Barrett’s esophagus in the Japanese population. Furthermore, we introduce the magnifying endoscopic classification （JES-BE classification） proposed by the Japan Esophageal Society, which provides endoscopic images to support clinical evaluation.

A 52-year-old woman underwent EGD due to epigastric discomfort. Multiple elevated lesions, approximately 5 mm in size, were detected from the upper gastric body to the fornix. Among the clustered polyps, a 10 mm polyp with a surface texture that was distinctly different from the others was identified. Magnified narrow-band imaging (NBI) revealed an uneven surface with papillary-to-nodular features. Based on the biopsy findings, which suggested a gastric-type adenoma, the patient underwent endoscopic mucosal resection (EMR). Histopathological analysis of the resected specimen confirmed a gastric-type adenoma with prominent nucleoli. Immunostaining was positive for MUC6 and MUC5AC and negative for MUC2 and CD10, supporting the diagnosis of gastric-type adenoma. However, the distinguishing features between gastric-type adenomas and adenocarcinomas remain unclear. It has been reported that gastric-type adenomas typically exhibit a papillary, granular surface microstructure surrounded by a white zone when observed under magnified NBI. To the best of our knowledge, this is a rare case of gastric-type adenoma arising from sporadic fundic gland polyposis in a patient who was not infected with Helicobacter pylori and had no genetic predisposition

A 73-year-old woman diagnosed with hepatitis C virus-related liver cirrhosis who had been receiving antiviral therapy for the previous 10 years was referred to our hospital for gastric cancer treatment. EGD revealed a well-demarcated superficial depressed lesion and nodular gastric varices (GV) on the body and fundus of the stomach, respectively. Lesion biopsy revealed well-differentiated adenocarcinoma. Endoscopically, the lesion was diagnosed as early gastric cancer localized within the mucosa and suitable for ESD. Prior to ESD, balloon-occluded retrograde transvenous obliteration (BRTO) of the GV was performed to prevent variceal bleeding. The lesion was successfully resected 2 months after BRTO with no remarkable complications or variceal bleeding. BRTO prior to ESD for gastric cancer was safe and effective for the prophylaxis against GV bleeding, and no difficulties were encountered during ESD.

A 75-year-old man who had undergone total left nephroureterectomy for left ureteral cancer one year earlier developed severe stenosis at the inferior duodenal angle due to metastatic recurrence. To relieve the obstruction, two uncovered stents were placed. The patient responded well to chemotherapy and immunotherapy; however, approximately 9 months after stenting, the stents migrated due to tumor shrinkage. Additionally, the patient developed a small bowel obstruction caused by the migrated stent and was admitted to the hospital on an emergency basis. Despite the placement of an ileus tube, the stent remained in the lower ileum and could not be excreted spontaneously. The stent was successfully retrieved via transanal single-balloon endoscopy, using the invagination method. The patient was discharged on postoperative day 8.

We report a case of a migrated duodenal stent causing intestinal obstruction that was successfully managed with single-balloon endoscopy.

As a gastrointestinal endoscopic modality, EUS enables the layer-by-layer visualization of the gastrointestinal wall, providing critical diagnostic data that are otherwise not obtainable through white-light or magnifying endoscopy. EUS is commonly employed in clinical practice, particularly in the staging of esophageal and gastric cancers, including the assessment of tumor invasion depth and lymph node metastasis.

However, since EUS is time-consuming and requires technical resources compared to conventional white-light endoscopy, careful selection of lesions for EUS is essential. This selection should be based on preliminary findings from white-light or magnifying endoscopy. Additionally, producing clear and reproducible EUS images that can be objectively interpreted is crucial for accurate diagnosis and appropriate treatment planning.

Based on their composition, bezoars, which are masses formed by the aggregation of foreign materials in the stomach, are classified as phytobezoars, trichobezoars, pharmacobezoars, or lactobezoars. In Japan, phytobezoars, composed of plant material, are the most common, with persimmon bezoars being particularly well-known. Persimmon tannins react with gastric acid to bind proteins, subsequently aggregating with food residues and hardening them into bezoars. While small bezoars may be naturally excreted, larger bezoars can cause various symptoms, including abdominal distension, vomiting, and gastrointestinal obstruction, which often require medical intervention. Traditionally treated surgically, bezoars can now be managed noninvasively owing to advancements in endoscopic techniques and the discovery of dissolution therapy using Coca-Cola^Ⓡ. In this study, we describe removal techniques using forceps and snares, fragmentation and cauterization with high-energy devices, and dissolution therapy with Coca-Cola^Ⓡ.

Objectives: The appropriate holistic management is mandatory for successful endoscopic ultrasound (EUS)-guided treatment of pancreatic fluid collections (PFCs). However, comorbidity status has not been fully examined in relation to clinical outcomes of this treatment.

Methods: Using a multi-institutional cohort of 406 patients receiving EUS-guided treatment of PFCs in 2010-2020, we examined the associations of Charlson Comorbidity Index (CCI) with in-hospital mortality and other clinical outcomes. Multivariable logistic regression analysis was conducted with adjustment for potential confounders. The findings were validated using a Japanese nationwide inpatient database including 4053 patients treated at 486 hospitals in 2010-2020.

Results: In the clinical multi-institutional cohort, CCI was positively associated with the risk of in-hospital mortality (P _trend＜0.001). Compared to patients with CCI=0, patients with CCI of 1-2, 3-5, and≥6 had adjusted odds ratios (95% confidence intervals) of 0.76 (0.22-2.54), 5.39 (1.74-16.7), and 8.77 (2.36-32.6), respectively. In the nationwide validation cohort, a similar positive association was observed; the corresponding odds ratios (95% confidence interval) were 1.21 (0.90-1.64), 1.52 (0.92-2.49), and 4.84 (2.63-8.88), respectively (P _trend＜0.001). The association of higher CCI with longer length of stay was observed in the nationwide cohort (P _trend＜0.001), but not in the clinical cohort (P _trend=0.18). CCI was not associated with the risk of procedure-related adverse events.

Conclusions: Higher levels of CCI were associated with a higher risk of in-hospital mortality among patients receiving EUS-guided treatment of PFCs, suggesting the potential of CCI in stratifying the periprocedural mortality risk.

Trial registration: The research based on the clinical data from the WONDERFUL cohort was registered with UMIN-CTR (registration number UMIN000044130).