Compared with the procedure in the upper or lower gastrointestinal tract, enteroscope insertion into the small bowel is technically challenging because of the longer luminal length and loose fixation by the mesentery. Capsule endoscopy, double- and single-balloon enteroscopy, and spiral enteroscopy, which are available since the 2000s have facilitated visualization of the entire small bowel. Motorized spiral enteroscopy (MSE) was introduced in 2016 and is performed at some hospitals in Japan since 2021. The diagnostic and insertion capabilities of MSE are similar to those of balloon-assisted enteroscopy; however, MSE requires a shorter procedural time. MSE and other small bowel endoscopy procedures are expected to further improve clinical practices of small bowel diseases.

The histopathologic characteristics of early pedunculated colorectal cancer often include a disrupted muscularis mucosae. Distinguishing such cases from other macroscopic types by measuring submucosal (SM) invasion depth is important in determining the treatment strategy.

When the muscularis mucosae can be identified, the depth of SM invasion is calculated as the distance between the deeper edge of the muscularis mucosae and the point of deepest invasion. When the muscularis mucosae cannot be identified, the depth of SM invasion is measured as the distance between the surface of the tumor and the point of deepest invasion. In polypoid tumors (0-Ip) with disrupted muscularis mucosae, the depth of SM invasion is considered the distance between the point of deepest invasion and the reference line (the fictitious line separating the tumor head and the pedicle). However, there is some discrepancy in these identification and estimation methods of the muscularis mucosae, even among pathologists.

Nonetheless, according to the current colorectal cancer treatment guidelines, endoscopic treatment is indicated if cTis or cT1a (SM invasion less than 1,000μm) is diagnosed, and surgical treatment including lymphadenectomy is recommended if cT1b (SM invasion deeper than 1,000μm) is diagnosed. However, some reports suggest that the invasion depth of protruded lesions, including early pedunculated colorectal cancer, is lesser than that of superficial lesions. It also reported that the risk of lymph node metastasis in pedunculated T1b cancer is lower than that in non-pedunculated T1b cancer. As pedunculated lesions are easier to endoscopically resect en bloc than other macroscopic lesions, endoscopic treatment is often performed first. Further research is needed to distinguish pedunculated from non-pedunculated lesions, including endoscopic diagnosis, indications for treatment, and methods to evaluate SM invasiveness.

A 66-year-old man was referred to our hospital for further evaluation of a polypoid lesion of the stomach detected on radiographic examination. Esophagogastroduodenoscopy revealed a broad-based elevated lesion (24mm) with a relatively steep but smooth surface and submucosal tumor-like morphology in the upper body of the stomach, with an edematous red apex and a shallow ulcer. Endoscopic ultrasonography revealed a lesion of low echogenicity with multiple aechoic images in the mucosal-submucosal layers, and we performed endoscopic resection using a snare followed by circumferential incision and submucosal dissection using ESD techniques. Histopathological examination of the resected specimen revealed that the polypoid lesion was composed of submucosal proliferation of cystically dilated gastric glands and fibromuscular elements. Based on these findings, we diagnosed the tumor as a hamartomatous inverted polyp (HIP). Only six cases (including the current case) of HIP with ulceration have been reported in Japan, which indicates the rarity of this form of HIP. The atypical ulcer observed in this case of HIP was probably attributable to mechanical stimulation. HIP is rare and is known to be complicated by cancer. Therefore, preoperative diagnosis is invariably challenging, and it is important to carefully devise the optimal treatment strategy.

A 64-year-old man, in good health his entire life, was admitted to our hospital with anorexia. Until three years ago, he had undergone an upper gastrointestinal series on an annual basis. An abdominal CT scan showed a calcified lesion in the rectum measuring 7 cm, and no evidence of free air. There were no abdominal symptoms indicating intestinal obstruction or perforation. The patient was hospitalized for endoscopic treatment and the barolith was removed after crushing it with a polypectomy snare. The diagnosis was confirmed after examination of the removed samples using infrared spectroscopy and scanning electron microscopy. Baroliths are prone to causing intestinal obstruction and perforation of the digestive tract, leading to severe complications. We report a case of barolith treated endoscopically.

A 41-year-old woman underwent preoperative contrast-enhanced CT for gallbladder stones. The CT scan suggested the presence of a protruding lesion in the cecum. CS revealed a 30mm pedunculated polyp with a wide stalk at the appendiceal orifice. Although biopsy findings suggested the presence of an inflammatory fibroid polyp, we could not deny that the lesion had neoplastic characteristics. Therefore, we decided to resect the lesion endoscopically for diagnostic purposes. Following two ligations near the base of the wide stalk using endoloops (Olympus, Tokyo, Japan), the polyp was removed using a snare. The patient had a postoperative fever (temperature of approximately 37°C); however, she recovered and was discharged 3 days after treatment. The final pathological diagnosis was a completely inverted appendix due to appendiceal endometriosis. One year later, endoscopic reexamination revealed no abnormality at the appendiceal orifice. We report an extremely rare case of a completely inverted appendix due to appendiceal endometriosis treated by endoscopic resection.

A 69-year-old man who underwent subtotal stomach-conserving pancreatoduodenectomy developed complete obstruction of the anastomosis during the 10^th postoperative month. He underwent cholangioscopy using single-balloon enteroscopy (SBE) and percutaneous transhepatic bile duct drainage; however, these procedures were unsuccessful. Therefore, we performed EUS-hepaticogastrostomy for internal fistulization. However, we detected intrahepatic stones, and considering the high risk of cholangitis, we performed release of the anastomotic stenosis from the jejunal aspect using a forward-viewing linear endoscopic ultrasound (FV-EUS). We subsequently performed anastomotic dilation and stone removal using SBE. Anastomotic dilation using FV-EUS in a patient with complete obstruction of a choledochojejunostomy facilitated subsequent stone removal and ongoing maintenance of the anastomosis.

Developed by Oyamaʼs in 2003, the HookKnife is a surgical device used during ESD. The HookKnife is useful in various gastrointestinal organs, such as the pharynx, esophagus, stomach, duodenum, and intestine. Besides the hook component of the knife, which allows for precision, the arm component is also useful as it allows comfortable and high-speed operation. It also allows us to use the vertical approach in the management of ulcer scars, where other devices were not adequate. Furthermore, the HookKnife was improved in 2005 with an added water supply function and was renamed the HookKnifeJ; this upgrade made the device even more useful. It is necessary to regularly practice these techniques, to improve oneʼs skills and be able to utilize the HookKnife without fail as the main device during ESD since it has proven to be very effective, especially in difficult cases.

More than 70% of patients with Crohnʼs disease are likely to develop small bowel lesions and both the monitoring and the control of these lesions are directly linked to the QOL in patients. Therefore, in the management of Crohnʼs disease, it is necessary to evaluate the condition of the entire small bowel with high accuracy, using a simple technique with a low burden to the patient. Although there is no test or marker that meets all of these requirements, double-balloon enteroscopy has been widely used as one of the monitoring tools for small bowel lesions in Crohnʼs disease patients and sometimes for endoscopic dilations. In our departments, retrograde contrast through double-balloon enteroscopy is routinely performed in addition to normal observation of the enteroscopy and could assist in evaluating the deep small bowel lesions beyond the scope. In this article, we introduce the procedure and tips for retrograde contrast through double-balloon enteroscopy in patients with Crohnʼs disease.

Since October 2019, I worked for 2 years as an endoscopist at Jigme Dorji Wangchuck National Referral Hospital, located at Thimphu, Bhutan. Though this period overlapped the COVID-19 pandemic, I was involved in approximately 4,000 cases of upper gastrointestinal (GI) endoscopy, 350 cases of colonoscopy, and 140 cases of ERCP.

In Bhutan, the infection rate of Helicobacter pylori is higher than 70%, and even among young adults the rate is alarming. Gastric cancer is a malignant disease with the highest mortality and is mostly detected in advanced stages. Therefore, a national flagship project that takes aim at the eradication of H. pylori and early detection of gastric cancer has been recently created. Endoscopic health examinations named Endoscopy Camp are being conducted every weekend.

In this article, we showed how upper GI endoscopy, colonoscopy, and ERCP is developing in Bhutan, which still lacks sufficient medical resources.

We hope more Japanese endoscopists take an active interest in developing countriesʼ medical care.

Objectives: This prospective multicenter study aimed to assess and compare the accuracy of tissue harmonic endoscopic ultrasonography (TH-EUS) and contrast-enhanced harmonic endoscopic ultrasonography (CH-EUS) for differentiating pancreatic carcinoma from other pancreatic tumors.

Methods: Consecutive patients with solid pancreatic tumors were prospectively enrolled between August 2013 and December 2014. To assess the accuracy of TH-EUS and CH-EUS, we compared four parameters of TH-EUS (fuzzy edge, irregular periphery, hypoechogenicity, and heterogeneous internal echogenicity) and four parameters of CH-EUS (hypoenhancement and heterogeneous enhancement in the early and late phases, respectively) to investigate which parameter of each method was most suitable to diagnose pancreatic carcinomas. Interobserver agreement and the diagnostic ability of pancreatic carcinoma using TH-EUS and CH-EUS were assessed and compared.

Results: A total of 204 patients were enrolled. For the diagnosis of pancreatic carcinoma, interobserver agreement by experts and nonexperts was 0.33-0.50 and 0.35-0.50 for TH-EUS, respectively, and 0.72-0.74 and 0.20-0.54 for CH-EUS, respectively. Irregular periphery was the most accurate diagnostic parameter among TH-EUS findings for differentiating pancreatic carcinomas, with sensitivity, specificity, and accuracy of 95.0%, 42.9%, and 78.9%, respectively. Late phase hypoenhancement was the most accurate diagnostic parameter among CH-EUS findings for differentiating pancreatic carcinomas, with sensitivity, specificity, and accuracy of 90.8%, 74.6%, and 85.8%, respectively. The accuracy of CH-EUS (late phase hypoenhancement) for diagnosis of pancreatic carcinoma was significantly higher than that of TH-EUS (irregular periphery) (p < 0.001).

Conclusion: In comparison with TH-EUS, CH-EUS increased the diagnostic ability and reproducibility for the diagnosis of pancreatic carcinoma. UMIN (000011124).