Several reports demonstrate the efficacy of lesion detection and characterization by image-enhanced endoscopy (IEE). The LASER and LED endoscopic systems appeared instead of endoscopic systems with Xenon light. These systems enable us to perform blue laser/light imaging (BLI), narrow-band imaging (NBI), linked color imaging (LCI), and texture and color enhancement imaging (TXI) for lesion detection and characterization. This chapter shows the efficacy of various IEE, including lots of clinical images and research reports.

With the development of next-generation sequencing, Japanese health insurance has covered comprehensive genomic profiling (CGP) using tumor tissue samples and liquid biopsy. We have them available in clinical practice. We have to consider CGP for precision medicine. For CGP using tumor tissue samples, more good quality tissue samples are necessary. EUS-guided tissue acquisition (EUS-TA) is expected to play an important role in diagnosis and as a sample collection method for CGP. At present, it seems essential to get sufficient tissue samples using a large-diameter fine-needle biopsy needle as much as possible. Further evidence needs to be accumulated for standardization of EUS-TA for CGP so that several patients can benefit from Precision Medicine.

Background and aim: Self-expanding metallic stents (SEMSs) have been available for use in Japan since January 2012. SEMS placement is performed as a bridge to surgery (BTS) or as a palliative treatment; however, only a few reports have been published about this method. The aim of this study was to clarify the efficacy and complications of SEMS placement for malignant colorectal obstruction.

Methods: From January 2012 to March 2021, SEMS placement was attempted in 180 patients with symptomatic colorectal obstruction. We retrospectively evaluated the efficacy and complications of SEMS placement performed at our institution.

Results: Technical success was achieved in 176 patients (97.8%), and clinical success was achieved in 165 patients (91.7%). A SEMS was placed as a BTS in 94 patients and for palliation in 86 patients. Four patients in the palliation group died within 24 h after SEMS placement. The main complications associated with SEMS placement were stent occlusion in 20 patients (11.4%, 20/176), bowel perforation in 11 patients (6.1%, 11/180), and stent migration in 4 patients (2.3%, 4/176). In the BTS group, bowel perforation was observed in two patients (2.1%, 2/94), one of whom required emergency surgery. In the palliation group, the median SEMS patency time was 221 days and the median patient survival time was 154 days.

Conclusion: SEMS placement is a relatively safe and effective method for managing malignant colorectal obstruction.

A 56-year-old woman was referred to the Department of Otolaryngology at our hospital for evaluation of postprandial sore throat and hematemesis; however, the cause remained undiagnosed. Upper gastrointestinal endoscopy revealed mucosal detachment 20-23 cm from the incisors concomitant with elevation of the detached mucosa. The mucosal detachment progressed and involved 2/3^rd of the esophageal circumference, and conservative treatment was continued. Eight days later, the detached mucosa was completely covered by normal mucosa and healed without scar stenosis or deformation.

Esophagitis exfoliativa is relatively rare; therefore, it is difficult to diagnose this disorder in acute upper gastrointestinal bleeding unless clinicians consider this disorder in the differential diagnosis.

A 79-year-old man was referred to our hospital for evaluation of a depressed lesion detected on esophageal radiography. EGD revealed a deep depressed well-marginated lesion containing multiple coarse granules on the left wall of the upper thoracic esophagus. Additionally, narrow-band imaging revealed a distended intra-papillary capillary loop within the depression. However, findings were not suggestive of an epithelial tumor, and the lesion remained undiagnosed based on the initial biopsy findings. Subsequent contrast-enhanced CT performed for systemic evaluation revealed enlarged mediastinal and celiac lymph nodes and multiple hepatic lesions, suggestive of multiple lymph node and liver metastases of a malignant tumor. However, EUS performed to evaluate the esophageal lesion revealed a hypoechoic mass that appeared to be a lymph node continuous with the esophageal depression, which indicated secondary esophageal tuberculosis with concomitant mediastinal lymphadenitis. Furthermore, EUS-FNA biopsy of the enlarged lymph nodes revealed a granuloma with caseous necrosis. Subsequent endoscopic re-examination and liver tumor biopsies revealed granulomas and Langhans giant cells. Therefore, the patient was clinically diagnosed with secondary esophageal tuberculosis associated with tuberculous lymphadenitis and hepatic tuberculosis and received antituberculosis therapy. Endoscopy performed 6 months later showed flattening of the depressed lesion and disappearance of the coarse granules, and CT revealed reduction in the size of the lymph nodes with disappearance of the liver lesions.

A 67-year-old man with rheumatoid arthritis presented with abdominal pain, diarrhea, and rectal bleeding 4 months after administration of abatacept (a recombinant fusion protein comprising a fragment of the Fc domain of human immunoglobulin G1 and the extracellular domain of human cytotoxic T-lymphocyte antigen 4). Colonoscopy revealed diffuse colitis mimicking ulcerative colitis. Other areas of the gastrointestinal tract were unaffected. We diagnosed the patient with abatacept-induced immune-mediated adverse event. Administration of prednisolone led to improvement in symptoms. Although rare, immune-mediated colitis should be considered in the differential diagnosis of patients with diarrhea or rectal bleeding observed during abatacept therapy.

A 62-year-old woman was hospitalized twice previously for fecal ileus, which improved using conservative treatment. She was transferred to our hospital as an emergency for evaluation of left abdominal pain. Abdominal radiography revealed a niveau image, and abdominal computed tomography showed a fecal mass in the descending colon, with significant fecal retention and expansion on the oral side. Colonoscopy showed fecaliths in the descending colon without any tumorous changes and stenosis. We observed fecal discharge after fecalith removal; therefore, the patient was diagnosed with fecal ileus. Gastrointestinal contrast-enhanced imaging performed on the 8^th day after admission revealed a giant colonic diverticulum, and the patient underwent laparoscopic descending colectomy. Histopathological examination of the resected specimen revealed fibrous thickening of the muscular layer of the diverticulum wall, suggestive of a true diverticulum. The possibility of a giant colonic diverticulum should be considered in patients with recurrent fecal ileus.

Mucosal incision-assisted biopsy (MIAB) is a technique that involves cutting the mucosa covered with subepithelial tumors (SET) to obtain biopsy specimens from the exposed lesions under endoscopic guidance. The diagnostic ability of MIAB for histopathological confirmation of gastric SETs is comparable with that of EUS-FNA, and this procedure is particularly useful for small lesions or in cases in which EUS-FNA-guided tissue retrieval is challenging. MIAB does not require specialized devices; therefore, most therapeutic gastrointestinal endoscopists are familiar with this technique, which is performed across many hospitals. However, few studies have reported this technique; therefore, large-scale studies with long-term follow-up are warranted in future to investigate the usefulness and safety of MIAB for standardization of the procedure.

The frequency of detection of superficial non-ampullary duodenal epithelial tumors is increasing in clinical practice. To date, small non-ampullary adenoma has often been observed by biopsy; however, biopsies may not be diagnostically accurate, and subsequent endoscopic resection may be challenging owing to the fibrosis after biopsies. Therefore, prompt removal is recommended for lesions that are amenable to safe and easy resection. Cold snare polypectomy (CSP) is one of the well-established standard treatments for colonic adenomas measuring ≤10mm. Notably, CSP is also an effective therapeutic strategy for management of lesions categorized as duodenal adenomas measuring ≤10mm. In this article, we outline the procedure and technical tips for duodenal CSP.

Objectives: To verify the efficacy and safety of red dichromatic imaging (RDI) in hemostatic procedures during endoscopic submucosal dissection (ESD).

Methods: This is a multicenter randomized controlled trial of 404 patients who underwent ESD of the esophagus, stomach, colorectum. Patients who received hemostatic treatments by RDI during ESD were defined as the RDI group (n = 204), and those who received hemostatic treatments by white light imaging (WLI) were defined as the WLI group (n = 200). The primary endpoint was a shortening of the hemostasis time. The secondary endpoints were a reduction of the psychological stress experienced by the endoscopist during the hemostatic treatment, a shortened treatment time, and a non-inferior perforation rate, in RDI versus WLI.

Results: The mean hemostasis time in RDI (n = 860) was not significantly shorter than that in WLI (n = 1,049) (62.3±108.1 vs. 56.2±74.6 s; P = 0.921). The median hemostasis time was significantly longer in RDI than in WLI (36.0 [18.0-71.0] vs. 28.0 [14.0-66.0] s; P = 0.001) in a sensitivity analysis. The psychological stress was significantly lower in RDI than in WLI (1.71±0.935 vs. 2.03±1.038; P ＜ 0.001). There was no significant difference in the ESD treatment time between RDI (n = 161) and WLI (n = 168) (58.0 [35.0-86.0] vs. 60.0 [38.0-88.5] min; P = 0.855). Four perforations were observed, but none of them took place during the hemostatic treatment.

Conclusions: Hemostatic treatment using RDI does not shorten the hemostasis time. RDI, however, is safe to use for hemostatic procedures and reduces the psychological stress experienced by endoscopists when they perform hemostatic treatment during ESD. UMIN000025134.