Current status and perspectives for endoscopic diagnosis of superficial nonampullary duodenal epithelial tumors

In recent years, there have been significant advances in the endoscopic resection (ER) procedures of superficial nonampullary duodenal epithelial tumors (SNADETs). A preoperative endoscopic diagnosis is thus deemed necessary in determining the indication for subsequent ER. For the histologic and endoscopic diagnosis of SNADETs, understanding the mucin phenotype is inevitable. Recently, two diagnostic algorithms for the differential diagnosis of SNADETs from nonneoplastic lesions under magnifying endoscopy with narrow‐band imaging have been proposed. In addition, various endoscopic approaches have been proposed to differentiate low‐ and high‐grade adenomas/carcinomas, including white light endoscopy, magnifying image‐enhanced endoscopy, and endocytoscopy. These methods, however, have not been standardized with respect to the classification of their findings and the validation of their diagnostic accuracy. Moreover, there are still concerns with respect to the histologic criteria required to establish a SNADETs diagnosis. Standardization in the histologic and endoscopic diagnosis of SNADETs is needed.