Search

The 2019 World Health Organization (WHO) Classification of Tumours of the Digestive System (5th edition) introduced the term "sessile serrated lesion" (SSL) to replace the term "sessile serrated adenoma/polyp" (SSA/P). SSLs are early precursor lesions in the serrated neoplasia pathway that result in colorectal carcinomas with BRAF mutations, methylation for DNA repair genes, a CpG island methylator phenotype, and high levels of microsatellite instability. Some of these lesions can rapidly become dysplastic or invasive carcinomas that exhibit high lymphatic invasion and lymph node metastasis potential. The 2019 WHO classification noted that dysplasia arising in an SSL most likely is an advanced polyp, regardless of the morphologic grade of the dysplasia. Detecting SSLs with or without dysplasia is critical; however, detection of SSLs is challenging, and their identification by endoscopists and pathologists is inconsistent. Furthermore, indications for their endoscopic treatment have not been established. Moreover, SSLs are considered to contribute to the development of post-colonoscopy colorectal cancers. Herein, the clinicopathological and endoscopic characteristics of SSLs, including features determined using white light and image-enhanced endoscopy, therapeutic indications, therapeutic methods, and surveillance are reviewed based on the literature. This information may lead to more intensive research to improve detection, diagnosis, and rates of complete resection of these lesions and reduce post-colonoscopy colorectal cancer rates.

The Japan Gastroenterological Endoscopy Society published the second edition of the "Guidelines for Colorectal Endoscopic Submucosal Dissection/Endoscopic Mucosal Resection" in 2019 to clarify the indications for colorectal endoscopic mucosal resection (EMR) and endoscopic submucosal dissection and to ensure appropriate preoperative diagnoses as well as effective and safe endoscopic treatment in front-line clinical settings. Endoscopic resection with electrocautery, including polypectomy and EMR, is indicated for colorectal polyps. Recently, the number of facilities introducing and implementing cold polypectomy without electrocautery has increased. Herein, we establish supplementary guidelines for cold polypectomy. Considering that the level of evidence for each statement is limited, these supplementary guidelines must be verified in clinical practice.

The Japan Gastroenterological Endoscopy Society developed the Guideline for Endoscopic Diagnosis of Early Gastric Cancer based on scientific methods. Endoscopy for the diagnosis of early gastric cancer has been acknowledged as a useful and highly precise examination, and its use has become increasingly more common in recent years. However, the level of evidence in this field is low, and it is often necessary to determine recommendations based on expert consensus only. This clinical practice guideline consists of the following sections to provide the current guideline: [I] Risk stratification of gastric cancer before endoscopic examination, [II] Detection of early gastric cancer, [III] Qualitative diagnosis of early gastric cancer, [IV] Diagnosis to choose the therapeutic strategy for gastric cancer, [V] Risk stratification after endoscopic examination, and [VI] Surveillance of early gastric cancer.

Suitable lesions for endoscopic treatment include not only early colorectal carcinomas but also several types of precarcinomatous adenomas. It is important to establish practical guidelines wherein preoperative diagnosis of colorectal neoplasia and selection of endoscopic treatment procedures are appropriately outlined and to ensure that actual endoscopic treatment is useful and safe in general hospitals when carried out in accordance with guidelines. In cooperation with the Japanese Society for Cancer of the Colon and Rectum, the Japanese Society of Coloproctology, and the Japanese Society of Gastroenterology, the Japan Gastroenterological Endoscopy Society compiled colorectal endoscopic submucosal dissection/endoscopic mucosal resection guidelines by using evidence-based methods in 2014. The first edition of these guidelines was published 5 years ago. Accordingly, we have published the second edition of these guidelines based on recent new knowledge and evidence.

It is well known that there are discrepancies in the diagnosis of gastrointestinal neoplasia between Western and Japanese pathologists. In the West, colorectal cancer (CRC) is defined by invasion through the muscularis mucosa into the submucosa, especially depending on the presence of desmoplasia. In Japan, however, CRC is defined based on a combination of nuclear and architectural abnormalities, regardless of invasion status. As a result, intramucosal carcinoma is diagnosed as high-grade dysplasia and even intramucosal carcinoma with poorly differentiated component is classified as 'Tis' in the West. It is logical and reasonable that the term 'T1' is used to currently describe intramucosal carcinoma. Use of the term 'high-grade dysplasia' for intramucosal CRC is outdated. In order to determine appropriate clinical treatment of CRC, the various risk factors of metastasis should be fully evaluated. With improved contributions and communication between pathologists and clinicians, overtreatment and inadequate follow up can be avoided. The discrepancies in the diagnosis of CRC between Western and Japanese pathologists may be addressed by an increase in East-West exchange. In addition, in the future, molecular analysis may also be useful for establishment of standardized diagnostic criteria of CRC.

Reported herein is the case of a 80-year-old man who had small squamous cell carcinoma in the esophagus. The lesion was initially detected as a irregular reddish elevated and flat area depicted by non-magnified white light endoscopy and observed as a brownish area with the narrow-band imaging system (NBI). The depth of elevated and depressed area in the lesion was predicted to be LSM to MM due to Inoue's classification of morphologic change of intrapapillary capillary loop (IPCL) under magnified NBI observation. The depth of another flat area was not able to predicted by Inoue's classification, and we used Arima's classification. We predicted the depth of invasion to be MM to SM1.by this classification. Endoscopic submucosal dissection (ESD) was carried out for the lesion. As a result, the endoscopic diagnosis completely accorded with pathological diagnosis. We could diagnose correctly by adding Arima's classification to Inoue's classification.

In Asian countries, squamous cell carcinoma is the most common type of esophageal cancer, and the incidence of gastric cancer remains have plateaued. To synthesize current information and to illustrate its clinical benefit of narrow band imaging (NBI) for diagnosis of superficial esophageal squamous carcinoma (SESCC) and early gastric cancer (EGC), a consensus conference was held by a panel of nine experts from Asian-Pacific countries. The expert's agreement suggested importance of interpretation of both vascular architecture and surface structure of the lesions and proper processor settings for endoscopic images. Zoom endoscopy was not regarded as absolutely necessary for detection of SESCC, but magnifying observation provided valuable information for characterization of detected lesions in the esophagus and the stomach. In general, NBI is useful for detection and characterization of SESCC, whereas it is beneficial mainly for characterization of EGC. Chromoendoscopy was found to be still worthwhile in certain situations, such as determination of the extent of SESCC by Lugol's staining, or detection and delineation of EGC by indigo carmine. NBI could replace chromoendoscopy in routine examination because it is easy to use and adds much information to conventional WLI, but it cannot eliminate chromoendoscopy when we make a final diagnosis for treatment decision-making. Consequently, the benefit of NBI or magnifying NBI is specific for the organ and the purpose of the examination, thus optimum indication and usage should be understood for maximum clinical benefit.

Upper endoscopy screening in an asymptomatic 56-year-old man showed a small, yellowish elevated lesion with a central depression on the posterior wall in the gastric cardia. Biopsy specimens from this lesion were suspicious of carcinoid tumor. We suspected this lesion to be a sporadic gastric carcinoid tumor with a diameter of 5 mm, limited to the mucosal layer. We then performed an endoscopic aspiration mucosectomy with a cap-fitted endoscope. Microscopically, the lesion obtained from the resected specimen was minimally invasive to the submucosa and showed highly differentiated columnar cells in irregularly anastomosing glands. Immunohistology was positive for pepsinogen-I, and MUC6, partially positive for H(+)/K(+)-ATPase, and negative for MUC5AC. In addition, it was positive for synaptophysin and CD56, and negative for chromogranin A. We finally diagnosed the patient as having gastric adenocarcinoma of fundic gland type (chief cell predominant type) with minimal invasion (100 µm) to the submucosa. Surveillance endoscopy with biopsy specimens and abdominal computed tomography at 1 year revealed no evidence of tumor recurrence. We herein report this rare case of gastric adenocarcinoma of fundic gland type (chief cell predominant type).

We report a case of gastric cancer complicated with very well differentiated adenocarcinoma containing signet ring cells. An endoscopic examination revealed a pedunculated polyp in the fornix of the stomach. A surgical operation was performed and the pathological findings showed very well differentiated adenocarcinoma mimicking gastric foveolae with a poorly differentiated component containing signet ring cells. This is the first case of pedunculated gastric cancer complicated with very well differentiated adenocarcinoma containing signet ring cells and also demonstrating a gastric foveolar phenotype.