Background Gastric mixed neuroendocrine–non-neuroendocrine neoplasms are rare malignant tumors. The lack of specific findings makes it difficult to diagnose endoscopically. We report the case of early gastric mixed neuroendocrine–non-neuroendocrine neoplasms treated by endoscopic submucosal dissection. Case presentation An 81-year-old Japanese female underwent esophagogastroduodenoscopy for screening and was treated with endoscopic submucosal dissection for the diagnosis of early gastric cancer. Histopathologically, the lesion was diagnosed as mixed neuroendocrine–non-neuroendocrine neoplasms (tubular adenocarcinoma 2 60%, endocrine cell carcinoma 40%), pT1b(submucosa (SM) 900 μm), pUL(−), Ly(+), v(−), pHM0, pVM0. After additional surgical resection without adjuvant chemotherapy, she has had no recurrences or metastases for 3 years. Conclusions Comparing narrow-band imaging magnified endoscopic findings with pathological findings, the depressed area with a lack of surface structure was consistent with the neuroendocrine cell carcinoma component, while narrow-band imaging magnification findings showed non-network vessels. In this case, we examined endoscopic findings of early stage mixed neuroendocrine—non-neuroendocrine neoplasms in detail and compared it with the pathological findings. We believe that these endoscopic findings contribute to the diagnosis of mixed neuroendocrine–non-neuroendocrine neoplasms and can lead to its early detection.

Background Perigastric abscess caused by delayed perforation after endoscopic submucosal dissection is a very rare complication. In principle, delayed perforation after endoscopic submucosal dissection is treated surgically. Herein, we report a case of perigastric abscess caused by delayed perforation after gastric endoscopic submucosal dissection that was treated conservatively, without perforation closure, and in which the patient was discharged from hospital in a short period. Case presentation A-74-year-old Asian man was diagnosed with having early gastric cancer on follow-up endoscopy and was admitted to our hospital for endoscopic resection. Endoscopic submucosal dissection was performed without intraoperative complications. On postoperative day 2, the patient complained of a slight abdominal pain localized to the epigastric region and a small amount of melena. A computed tomography scan revealed the presence of free air in the peritoneal cavity, and a little fluid collection abutting the dorsal area of the stomach. An endoscopy examination showed a deep ulcer with the accumulation of pus, suggesting a perforation in the post-endoscopic submucosal dissection ulcer. We diagnosed a perigastric abscess, caused by delayed perforation after endoscopic submucosal dissection, and opted for conservative treatment, leaving the perforation site open to allow spontaneous drainage from the abscess into the stomach. A follow-up computed tomography scan revealed an encapsuled and localized perigastric abscess on postoperative day 5, and the disappearance of the free air and the regression of the perigastric abscess on postoperative day 7. A follow-up endoscopy examination on postoperative day 7 showed the closure of the perforation. Finally, surgery was avoided, and the patient was discharged on postoperative day 14, after a relatively short hospital stay. Conclusion Regarding the treatment of perigastric abscess, caused by delayed perforation after endoscopic submucosal dissection, leaving the perforation site open to allow spontaneous drainage may shorten the conservative treatment period.

Background and study aim: Endoscopic submucosal dissection (ESD) with conventional endoscopes is often difficult for pharyngeal cancers, on account not only of the narrow working space, but also poor maneuverability of the endoscope in the pharynx due to interference by the endotracheal tube and/or hyoid bone. However, we considered that the above problems could possibly be resolved by the use of an ultrathin endoscope for ESD of superficial pharyngeal cancers. The aim of this prospective interventional study was to investigate the feasibility of ESD for superficial pharyngeal cancer using an ultrathin endoscope. Patients and methods: This feasibility study was conducted at NTT Medical Center Tokyo between June 2020 and September 2021, and data of a total of 20 consecutively superficial pharyngeal cancers were analyzed. The primary outcome measure was the R0 resection rate. The ESD completion rate, en-bloc resection rate, procedure time, and frequency of intraoperative and postoperative adverse events were also evaluated as the secondary outcome measures. Results: The data of 16 patients with 20 lesions were included in the analysis. All of the lesions were successfully resected by ultrathin endoscope ESD, and the en-bloc and R0 resection rates were 100% and 85.0% (17/20), respectively; the procedure time was 37.8 ± 28.2 minutes. No intraoperative or postoperative adverse events were encountered in any cases. Conclusions: ESD using an ultrathin endoscope is feasible for superficial pharyngeal cancers and may become established as one of the safe and effective treatment options for these cancers in the future. (Clinical trial registration number:UMIN000040961.)

While duodenal neoplasms of the gastric phenotype are uncommon and their natural history is unknown, gastric neoplasms of gastric phenotype reportedly grow rapidly and can invade the submucosa. Several studies suggest that duodenal neoplasms of gastric phenotype might have a high risk of deep invasion and lymph node metastasis. Duodenal neoplasms of gastric phenotype might also have a high biological malignancy and likely require early treatment if detected. Here, we report two cases of intramucosal duodenal carcinoma with a gastric phenotype that grew rapidly but was successfully resected endoscopically.

Endoscopic submucosal dissection (ESD) is the standard endoscopic treatment for early esophageal cancer. Esophageal stricture often occurs at the site of ESD for large lesions. When treating a metachronous lesion appearing at the severe stricture, it may be difficult to negotiate a conventional endoscope through the stricture. Using a thin endoscope may be a useful strategy for such lesions, though ESD using a thin endoscope is challenging because of poor maneuverability. Herein, we report a case of successful ESD for early esophageal cancer at the severe stricture, using a conventional endoscope. A 72‐year‐old man with a previous history of ESD for esophageal cancer and a post‐ESD esophageal stricture was referred to our hospital for metachronous early esophageal cancer. The lesion, 10 mm in diameter, was located at the stricture with a slight distal extension. Conventional endoscopes could not be negotiated through stricture. Therefore, submucosal dissection was performed from the oral to the anal aspect of the lesion, as far as possible. After completion of submucosal dissection of the oral aspect of the lesion and part of the lesion located on the stricture, the severe stricture was released, allowing the passage of conventional endoscope, and ESD of the entire lesion was completed en bloc. Histopathological examination showed squamous cell carcinoma, pT1a‐LPM. Stricture due to scarring may occur during the regeneration process of the defective mucosa, muscularis mucosa, and submucosal layer. Therefore, incision and dissection of the contracted mucosa, mucularis mucosa, and submucosal layer would release the stenosis.