The validity of the surgical indication for intraductal papillary mucinous neoplasm of the pancreas advocated by the 2017 revised International Association of Pancreatology consensus guidelines

Purpose: This study was performed to evaluate the surgical indication for intraductal papillary mucinous neoplasm (IPMN) advocated by the 2017 revised International Association of Pancreatology consensus guidelines (IAPCG2017). Methods: The medical records of 63 patients who underwent pancreatectomy for IPMN were retrospectively reviewed. Results: Thirteen patients had main-duct IPMN, 25 had mixed IPMN, and 25 had branch-duct IPMN with frequencies of high-grade dysplasia or invasive carcinoma of 62, 24, and 28%, respectively. The sensitivity and specificity of high-risk stigmata for high-grade dysplasia or invasive carcinoma advocated by the IAPCG2017 were 90 and 67%, respectively. Of 17 patients with invasive carcinoma, all patients had high-risk stigmata, and 16 had an enhanced mural nodule (MN) of ≥ 5 mm. The sensitivity and specificity of a ≥ 5-mm enhanced MN for predicting invasive carcinoma were 94% and 87%, respectively. Conclusions: Introducing a size threshold for enhanced MNs into the assessment of high-risk stigmata increases the specificity without jeopardizing the sensitivity. The surgical indication for any type of IPMN may be determined using only a ≥ 5-mm enhanced MN. When the type of IPMN is classified strictly, about half of IPMNs are mixed type, and most are benign. The surgical indication for mixed IPMN should be reconsidered.