The endocytoscopy system (ECS) enables observation of surface epithelial cells with vital staining, thus realizing the concept of optical biopsy. The first-generation ECS was developed in 2003, and four ECS prototypes have been developed to solve the problems of each prototype. The fourth-generation ECS (GIF-H290EC) allows high-definition observation under 500 times magnification. The GIF-H290EC was released on the market in 2018. Concerning the esophagus, ECS can clearly demonstrate the shape of cell nuclei. Accuracy of more than 90% for distinguishing esophageal malignancy was noted based on observation of both “nuclear density” and “nuclear atypia”.

Concerning the stomach, removal of surface mucous still remains as a considerable problem. Devising the dye for vital staining has improved the staining ability for the stomach and has allowed us to assess “structural destruction”, “loss of polarity of cell arrangement”, and “cell abnormality”.

Only a few articles on ECS observation of the duodenum have been published. However, characteristic findings that reflect the histological features can be obtained in cases with celiac disease and duodenal neoplasms.

ECS enables pathological diagnosis in vivo in real time. Using ECS, we can perform “microscopic diagnosis” in addition to the conventional “macroscopic diagnosis”.

The number of patients with inflammatory bowel disease (IBD), a chronic inflammatory disease of unknown cause, continues to increase. A new therapeutic strategy aimed at improving long-term prognosis is necessary. The importance of a treatment strategy based on treat to target (T2T), setting a concrete therapeutic goal, has been advocated. Endoscopic remission has been set as a standard treatment target, and further studies are being performed as to whether histological remission should be a treatment target. Appropriate monitoring is also important for T2T treatment strategies. Stool biomarkers such as calprotectin and fecal immunochemical test can be used. Monitoring of small bowel lesions has become possible due to the development of capsule endoscopy and small intestinal balloon endoscopy. In addition, cross-sectional imaging has been developed and used as a diagnostic and monitoring tool in daily practice. In terms of treatment, options such as 5-aminosalicylic acid preparation and budesonide preparation are increasing, and new evidence including NUDT 15 gene polymorphism has been accumulating for thiopurine treatment. Furthermore, with the success of anti-TNFα antibody agents, molecular targeting therapeutic agents against IBD are being developed.

A 41-year-old man with vomiting of blood was referred to our hospital. Upper gastrointestinal endoscopy revealed spurting bleeding from a submucosal tumor-like, protruded lesion in the posterior wall of the stomach. The patient was initially thought to have varices, and ligating hemostasis using an o-ring was performed. From the results of abdominal contrast computed tomography, bleeding from an enlarged left gastric artery branch that branches from the aorta was suspected. The lesion re-ruptured 11 hours later. Therefore, after performing re-ligation by the same procedure, gastrectomy and splenectomy were performed. Pathological examination revealed a change in segmental arterial mediolysis.

We present the case of a 70-year-old man who had undergone upper gastrointestinal endoscopy and was found to have a 7 mm, discolored, submucosal tumor-like elevated lesion on the lesser curvature of the upper gastric body ten years ago. Since then, annual follow-up endoscopy showed no change in its size or shape, but 10 years after the initial examination, it had expanded to 9 mm in diameter and formed depressed areas. A biopsy specimen from the depressed lesion was diagnosed as gastric adenocarcinoma of fundic gland type. One month after the biopsy, magnifying endoscopy with narrow band imaging (NBI) detected an irregular microsurface (MS) and microvascular (MV) pattern in this lesion, and endoscopic submucosal dissection (ESD) was performed. Histopathologically, the tumor developed mainly in the deep layer of the lamina propria, appeared on the mucosal surface in depressed areas, and partially infiltrated into the submucosal layer. Few reports have examined changes in endoscopic images and NBI-enlarged findings in the long-term follow-up of a gastric adenocarcinoma of fundic gland type, and this is considered to be a valuable case.

A 64-year-old male was referred to our hospital with a weight loss of 23 kg over the previous nine months due to anorexia and diarrhea. The patient had been taking olmesartan for ten years for the treatment of hypertension. Esophagogastroduodenoscopy and colonoscopy did not reveal any abnormalities, but capsule endoscopy demonstrated villous atrophy in the duodenum and the small intestine. Duodenal biopsy showed no amyloid deposition nor atypical lymphocytes, and the patient tested negative for bacteria in stool culture and ova, suggesting celiac disease. Since the patient was on olmesartan, sprue-like enteropathy associated with olmesartan was suspected, the clinical presentation of which is similar to celiac disease. Olmesartan was discontinued, and his anorexia, diarrhea, and weight loss improved. Capsule endoscopy performed four months later demonstrated reduced villous atrophy in the duodenum and the small intestine. In patients receiving olmesartan therapy who develop chronic diarrhea, sprue-like enteropathy associated with olmesartan should be considered as a potential cause. Capsule endoscopy was effective in evaluating small intestinal villous atrophy.

A 73-year-old woman complained of diarrhea, bloody stools, and weight loss. Colonoscopy revealed diverse elevated lesions in the entire colon. Esophagogastroduodenoscopy revealed whitish nodules and granules from the horizontal part of the duodenum to the bulbus. The pathological diagnosis based on the biopsy specimens from the colon and duodenal lesions was follicular lymphoma. Further examination revealed enlargement of multiple lymph nodes, invasion of lymphoma cells to the spleen, and bone marrow infiltration. Conclusively, we diagnosed her with follicular lymphoma grade 1, Ann Arbor stage IVB, and as being at high risk in the Follicular Lymphoma International Prognostic Index. Six courses of chemotherapy (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone therapy) were administered, and complete remission was achieved based on the subsequent image-based examination. Cases with findings of follicular lymphoma typical of the duodenum and multiple lymphomatous polyposis in the entire colon are relatively rare.

A 71-year-old woman was admitted to our hospital to investigate the cause of liver dysfunction. Imaging examinations revealed the thickened wall of the lower bile duct and a tumor in the duodenal papilla. The cytology of the bile juice and brushing of the lower bile duct led to the diagnosis of adenocarcinoma. We diagnosed lower bile duct cancer from these examinations and performed pylorus-preserving pancreaticoduodenectomy. The resected specimen revealed a mass of 15mm in the duodenal papilla. Histological examination showed poor atypicality and smooth muscle and fibrous tissue proliferation. Therefore, it was finally diagnosed as adenomyomatous hyperplasia (AMH). We experienced this rare case of AMH in the duodenal papilla. We report this case with consideration of the literature.

A 32-year-old woman with epigastric pain, back pain, and hyperamylasemia (1,627 IU/L) was referred to our hospital. Computed tomography (CT) revealed a 43 × 37-mm hypovascular mass in the pancreas head, dilated tail of the main pancreatic duct, and enlarged mesenteric and paraaortic lymph nodes. Upper gastrointestinal endoscopy revealed a white, granular, small elevated lesion in the duodenum, which was thought to be duodenal follicular lymphoma. The patient also developed obstructive acute pancreatitis due to enlarged lymph nodes around the pancreas, which was treated with placement of a pancreatic duct stent. Positron emission tomography-CT showed abnormal uptake in the pancreatic mass, in a right axillary lymph node, and in bilateral inguinal and intraabdominal lymph nodes. The soluble interleukin (IL)-2 receptor level was also elevated. Transformation of follicular lymphoma which was diagnosed from the pathological findings of the right axillary lymph node, was treated with the R-CHOP regimen.

Endoscopic inside stent placement is a method of deploying a biliary stent above the major papilla. Its efficacy has not been elucidated yet; however, several recent retrospective studies have shown promising results. Benign biliary stricture and malignant hilar biliary stricture are good indications for the procedure. Endoscopists should choose the appropriate stents that fit the shape of the stricture and the bile duct, and multiple stent placement is preferable for hilar biliary stricture. These tips will prevent dislocation of the stents. In addition, although dedicated plastic stents with a thread attached are beneficial for removing the stents from the bile duct as required and are now available, endoscopists should learn the technical tips of removing them. It is very important to learn the evidence of the benefits and drawbacks of endoscopic inside stent placement that have accumulated at this point and to perform the procedure appropriately.

Background and Aim: Pancreatic ductal adenocarcinoma (PDAC) is difficult to detect in its early stages with the poorest prognosis of all cancers. To improve the prognosis, a precise diagnosis is needed when we suspect PDAC. Although endoscopic ultrasound-guided fine-needle aspiration biopsy (EUS-FNA) is a widely accepted modality for the diagnosis of PDAC, its sensitivity is 85-89%, and approximately 10% of PDAC cases cannot be diagnosed. The main causes that interrupt the diagnosis of PDAC by using EUS-FNA are tumor size, presence of a vessel or the main pancreatic duct along the puncture route, and difficulty in withdrawing anticoagulant. Pancreatic juice cytology (PJC), the sensitivity of which is 33.3-65.8%, is a method for the diagnosis of PDAC cases in which carrying out of EUS-FNA is difficult. To diagnose PDAC appropriately, we need to improve the diagnostic ability of PJC.

Methods: We examined PJC using synthetic secretin for 138 cases of pancreatic tumor and pancreatic non-cancerous diseases.

Results: Sensitivity of PJC improved from 50.9% to 74.0% as a result of synthetic secretin loading, and 13 PDAC cases that had not been able to be diagnosed with EUS-FNA could be diagnosed pathologically by PJC. Although there were 12 patients with mild pancreatitis (8.7%) as a complication, all were relieved with conservative treatment.

Conclusion: Adding synthetic secretin to PJC is useful for cases in which it is difficult to carry out EUS-FNA for PDAC.