LAUSR

213 Intraductal papillary mucinous neoplasm (IPMN) of the pancreas is subdivided based on the site of involvement within the main pancreatic duct (MPD) as follows: the main duct (MD), the branch duct, or a mixture of the two. Surgical resection is strongly recommended for MD-IPMNs because of their high malignant potential. In a previous surgical series, the malignancy rate of MD-IPMN was 36–100%. However, this may be an overestimation of the actual risk. Surgical series can present selection bias, as patients who undergo surgical resection are more likely to present with criteria suspicious for progression. The international consensus guidelines for managing IPMN recommend resecting all MD-IPMNs with an MPD diameter >10 mm, jaundice, or mural nodules. Mural nodules have been established as a predictor of malignancy in MD-IPMNs, with high sensitivity (59–92%) and specificity (60–96%). However, all MD-IPMNs are not diagnosed to be malignant, despite being surgically resected using these criteria. In the current issue of Clinical Endoscopy, Kishimoto et al. reported the efficacy of endoscopic findings from peroral pancreatoscopy (POP) with video and narrow-band imaging (NBI) for mural nodules to predict the progression of IPMNs with a dilated MPD. They classified mural nodules into four types based on the morphology of protrusion, using POP. Cytology/ biopsy was also performed during POP. Malignancy was not diagnosed by cytology/biopsy in any of the seven patients with mural nodules of sessile morphology. They underwent surveillance only, without surgical resection, and adenocarcinoma developed in one patient (14%) during the follow-up period (mean: 81 months). The authors suggested that a benign or malignant diagnosis is possible in MD-IPMN depending on the degree of elevation of the mural nodule observed by POP. With remarkable technological innovation and progress in endoscopic equipment, endoscopic morphology with image-enhanced endoscopy provides high diagnostic yields and has replaced pathological diagnosis for stomach and colon tumors. Recently, peroral cholangiopancreatoscopy (POCP) has shown notable development in terms of technical difficulty and image quality. Subsequently, the diagnostic and therapeutic roles of POCP have continued to expand and evolve. One of the popular indications for peroral cholangioscopy (POC) is the visual diagnosis of indeterminate biliary strictures. In previous studies, visual assessment using POC has shown high sensitivity (78–95%) and high specificity (73–96%) for the diagnosis of malignant biliary stricture. Furthermore, image-enhanced technologies such as NBI and I-scan are useCOMMENTARY