Helicobacter pylori (H. pylori) infection is closely associated with gastric cancer, and endoscopic diagnosis of H. pylori infection is essential to determine the risk of gastric cancer. The Kyoto Classification of Gastritis includes 19 typical endoscopic findings of gastritis based on a patientʼs H. pylori status including H. pylori-uninfected, -infected, and -post-infected statuses. Regular arrangement of collecting venules is a typical endoscopic finding observed in H. pylori-uninfected individuals. H. pylori-infected patients typically show atrophy and sometimes intestinal metaplasia, nodularity, enlarged folds with diffuse redness and sticky mucus production, whereas patients with previous H. pylori infection present disappearance of diffuse redness and sometimes map-like redness is observed.

In addition, this revised edition of the Classification covers gastric mucosal changes other than those caused by H. pylori infection. The Kyoto Classification of Gastritis is useful for diagnosis of H. pylori infection and risk assessment of gastric cancer in endoscopic practice, and is also expected to be useful for student education and training of endoscopists.

Endoscopists have an increasing chance of seeing patients with a rectal neuroendocrine tumor (NET). However, there are many issues about rectal NET on which no consensus has been reached, including diagnosis, treatment, and management following treatment. With regard to indications for endoscopic treatment, further discussion is required about whether rectal NETs sized 1-1.5cm can be an indication for endoscopic treatment. On the other hand, it is widely accepted that rectal NETs sized ＜1cm without muscularis invasion are good indications for endoscopic treatment. For rectal NETs sized ＜1cm without muscularis invasion, a modified endoscopic mucosal resection (EMR) technique is recommended, such as endoscopic submucosal resection with ligation device (ESMR-L) or endoscopic mucosal resection using a cap-fitted endoscope (EMR-C), due to its effectiveness, safety and low burden for patients. Management following endoscopic treatment is decided based on the results of pathological evaluation of the endoscopically resected specimen. However, depending on the conditions of cell proliferation and lymphovascular invasion, it may be difficult to judge whether radical surgery is required following endoscopic treatment or not. Particularly regarding lymphovascular invasion, it has been reported that lymphovascular invasion is frequently diagnosed even in patients with small rectal NET G1 lesions without muscularis invasion by using immunohistochemical and special staining in pathological evaluation. Further studies on the clinical significance of lymphovascular invasion in patients with rectal NETs are warranted.

We could observe chronological changes of early laryngeal cancer over a 20-month period by narrow-band imaging (NBI). A 74-year-old man with unresectable advanced esophageal cancer was treated by chemoradiation therapy. After 5 courses of fluorouracil and cisplatin with radiation therapy, a brownish area (BA) of about 2 mm in diameter was detected on the left aryepiglottic fold during gastroduodenoscopy to evaluate the effect of chemotherapy for esophageal cancer. Thirty-five days after detection of the BA, the lesion had enlarged to about 3 mm and obtained a clearer margin. One hundred fifty-five days after detection, the lesion had enlarged to about 8mm and an NBI magnifying image revealed meandering dilated vessels of irregular caliber with varied form. At this point, we diagnosed the BA as a neoplastic lesion; however, pathologic examination of a biopsy specimen revealed non-neoplastic inflammatory squamous epithelium. The advanced esophageal cancerous lesion was judged as stable disease, and we decided to follow the small BA lesion. Two hundred thirty-six days after detection, the lesion had enlarged to about 10 mm and obtained a more irregular edge. Five hundred thirty-four days after detection, the lesion had enlarged and progressed to the left ventricular fold. Six hundred one days after detection, a biopsy specimen was obtained and pathologic examination revealed squamous carcinoma. The recent widespread availability of NBI magnifying gastroduodenoscopy has resulted in increased detection of small asymptomatic brownish areas in the pharyngolarynx. These small BAs have been treated by follow-up, biopsy or resection. Pathologic examination of biopsy specimens of small BAs does not always reveal an accurate diagnosis. It is often difficult to obtain biopsy specimens in the pharyngolarynx. Therefore, endoscopists have to follow BAs in the pharyngolarynx that are suspected as being neoplastic lesions regardless of their size.

A 69-year-old male patient underwent endoscopic submucosal dissection (ESD) of gastric adenoma in May 2012. The pathological diagnosis was tubular adenoma, and curative resection was performed. After ESD, it was thought that Helicobacter pylori was spontaneously eradicated. In April 2014, a 40mm hyperplastic polyp was detected at the resection site. The polyp grew to 50mm in September 2015, at which time we performed ESD of the polyp. However, one year later a similar hyperplastic polyp developed again. We performed ESD of the recurrent polyp and injected 80mg of triamcinolone acetonide locally at the site of the post-ESD ulcer. Thereafter, we have not observed recurrence of polyp. It was considered that local steroid injection prevented the development of hyperplastic polyp at the resection site after ESD.

An 18-year-old man (Case 1) came to our hospital for diarrhea and right lower abdominal pain. A 21-year-old woman (Case 2) came to our hospital for diarrhea and high fever. In both cases, their endoscopic examination revealed extensive shallow ulcers on a swollen Peyerʼs patch in the terminal ileum, and intramucosal hemorrhage and edema were observed in the entire colon. Their colonic endoscopic findings had characteristics of Campylobacter colitis. Campylobacter jejuni organisms were detected in cultures of intestinal fluids in both cases. In the literature, there was only one case report of Campylobacter enterocolitis with extensive ulceration in the ileum. We report two very rare cases.

Esophageal endoscopic submucosal dissection (ESD) is technically demanding because of the narrow esophageal lumen and thin esophageal wall. The IT knife nano has a shorter blade and smaller backside electrode on the ceramic tip compared with the standard IT2 knife, facilitating esophageal ESD. It allows us to perform safe and efficient mucosal incision and submucosal dissection. It also allows for easy application of the long blade to the submucosal space.

Esophageal ESD is performed with the patient in the left lateral position under deep sedation using propofol or general anesthesia. The use of deep sedation using propofol or general anesthesia is part of the protocol for ESD established at our hospital. First, after sufficient submucosal injection of sodium hyaluronate, semi-circumferential mucosal incision of the left side of the esophagus is performed using the IT knife nano and a dual knife. It is not necessary to press the ceramic tip of the IT knife nano against the submucosa as much as in gastric ESD. Next, submucosal dissection of the left side of the esophagus is performed. The tissue of the submucosa is hooked and lifted with the long blade of the IT knife nano, and the submucosal layer is dissected from inside to outside up to the left edge of the submucosal plane. This procedure is continued up to the distal left edge to shift the lesion against gravity, preventing muscle injury and perforation. After completion of submucosal dissection, the clip-and-line traction technique is routinely performed. This procedure provides sufficient tissue traction proximally and opens the submucosal space, allowing safe and efficient submucosal dissection. During esophageal ESD, it is very important to control carbon dioxide insufflation, which should be less than that during screening and diagnostic esophagogastroduodenoscopy, keeping the submucosa thick and soft.

The IT knife nano is a very helpful device for safely performing esophageal ESD. The IT knife nano can also be used to train less experienced endoscopists in performing esophageal ESD. However, expert hands are required for challenging cases such as an esophageal lesion with severe fibrosis.

Background and Aim: Treatment efficiency of walled-off necrosis (WON) using endoscopic ultrasound-guided drainage (EUS-D) with a double pigtail stent (DPS) is limited. Endoscopic necrosectomy is often carried out if EUS-D fails. However, endoscopic necrosectomy is associated with significant morbidity and mortality. Thus, we developed transmural nasocyst continuous irrigation (TNCCI) as an alternative therapeutic option for WON. This study aimed to evaluate the usefulness of TNCCI therapy for WON.

Methods: Between April 2009 and March 2018, 19 of 39 patients admitted with WON underwent EUS-D. Ten consecutive patients also received TNCCI therapy (TNCCI group) between May 2015 and March 2018. TNCCI was carried out by inserting an external tube from the gastroduodenal lumen into the WON under endoscopic ultrasonography guidance and then continuously irrigating the WON with saline at a rate of 40 ml/h. Nine consecutive patients who underwent EUS-D without TNCCI therapy between April 2009 and April 2015 were used for comparison (control group). Various parameters were compared between the TNCCI and control groups.

Results: Time taken to reduce WON (6 vs 32 days, P＝0.001), implementation rate of endoscopic necrosectomy (0％ vs 55.6％, P＝0.01), and number of endoscopic necrosectomy sessions per patient (0 vs 0.8±1.0, P＝0.008) were significantly lower in the TNCCI group than in the control group.

Conclusions: Walled-off necrosis can be effectively and safely treated by endoscopic drainage with a DPS and TNCCI. This technique can be an alternative therapeutic option before carrying out endoscopic necrosectomy.