Gastropericardial fistula is generally associated with benign gastric diseases and is an uncommon complication of gastric adenocarcinoma. Pericarditis and cardiac tamponade are the ultimate outcome, with extremely high mortality rates. We report a 47-year-old man with gastric adenocarcinoma who had completed radiotherapy and was on scheduled chemotherapy, who presented with fever and chest pain. Gastric adenocarcinoma complicated with gastropericardial fistula and Candida albicans pericarditis were diagnosed and treated successfully with conservative management. Initial chest radiography and computed tomography (CT) revealed no evident pericardial air or fluid. However, follow-up panendoscopy 2 weeks later revealed a malignant ulcer with a fistula opening over the lesser curvature of the high body of the stomach. Subsequent chest radiography and CT revealed pneumopericardium with fluid accumulation. Emergent CT-guided pericardial drainage was performed. The fluid was positive for Candida albicans. Total parenteral nutrition and antifungal therapy were administered. The patient refused surgical intervention and survived with medical management alone. This case demonstrates that first, panendoscopy may be safely performed in patients with gastropericardial fistula without significant risk of cardiac tamponade; second, although early diagnosis of gastropericardial fistula is generally important, delayed recognition may not lead to devastating outcomes even in the absence of surgical intervention.

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A comparative study of polypoid and flat colorectal cancers less than 20 mm in size was made. A review of the characteristics of 56 polypoid cancers and 29 flat cancers treated between April 1989 and January 1996 was performed. Both groups of cancers showed similar age and location distribution. Polypoid cancers were more likely to be well differentiated (38%) than were flat cancers (17%) (P < 0.05). Flat cancers were more likely to have reached the serosa (52% vs 12%; P < 0.01) and also demonstrated a higher frequency of lymph node involvement (41% vs p 9%) (P < 0.01) when compared to polypoid cancers. Flat colorectal cancers belong to a distinct subset which demonstrates greater biological aggressiveness than polypoid cancers of equivalent size.

Colonoscopies reduce the incidence of colorectal cancer through early recognition and resecting of the colon polyps. However, the colon polyp miss detection rate is as high as 26% in conventional colonoscopy. The search for methods to decrease the polyp miss rate is nowadays a paramount task. A number of algorithms or systems have been developed to enhance polyp detection, but few are suitable for real-time detection or classification due to their limited computational ability. Recent studies indicate that the automated colon polyp detection system is developing at an astonishing speed. Real-time detection with classification is still a yet to be explored field. Newer image pattern recognition algorithms with convolutional neuro-network (CNN) transfer learning has shed light on this topic. We proposed a study using real-time colonoscopies with the CNN transfer learning approach. Several multi-class classifiers were trained and mAP ranged from 38% to 49%. Based on an Inception v2 model, a detector adopting a Faster R-CNN was trained. The mAP of the detector was 77%, which was an improvement of 35% compared to the same type of multi-class classifier. Therefore, our results indicated that the polyp detection model could attain a high accuracy, but the polyp type classification still leaves room for improvement.

Water exchange (WE) and artificial intelligence (AI) have made critical advances during the past decade. WE significantly increases adenoma detection and AI holds the potential to help endoscopists detect more polyps and adenomas. We performed an electronic literature search on PubMed using the following keywords: water-assisted and water exchange colonoscopy, adenoma and polyp detection, artificial intelligence, deep learning, neural networks, and computer-aided colonoscopy. We reviewed relevant articles published in English from 2010 to May 2020. Additional articles were searched manually from the reference lists of the publications reviewed. We discussed recent advances in both WE and AI, including their advantages and limitations. AI may mitigate operator-dependent factors that limit the potential of WE. By increasing bowel cleanliness and improving visualization, WE may provide the platform to optimize the performance of AI for colonoscopies. The strengths of WE and AI may complement each other in spite of their weaknesses to maximize adenoma detection.