LAUSR

Objective Noninvasive intraductal papillary mucinous neoplasms (IPMNs) theoretically do not metastasize. The purpose of this study is to preoperatively distinguish invasive carcinomas associated with IPMN from noninvasive IPMN. Methods A total of 131 patients who underwent surgical resection for IPMN were retrospectively analyzed to identify the predictors of invasive carcinoma, based on the International Association of Pancreatology Consensus Guidelines. Results Of the 131 patients, 29 (22%) had invasive carcinomas and 102 (78%) had noninvasive IPMN. An enhancing mural nodule (MN) greater than or equal to 5 mm, obstructive jaundice, an abrupt change in the caliber of the pancreatic duct (PD) with distal pancreatic atrophy, and lymphadenopathy were the significant predictors of invasive carcinoma in univariate analysis. The optimal cutoff value for the size of the enhancing MN to differentiate invasive carcinoma was 13 mm. In multivariate analysis, enhancing MN greater than or equal to 13 mm, obstructive jaundice, and an abrupt change in the PD caliber were the independent predictors. When all these factors were absent, only 17% were invasive carcinomas. Conclusions Enhancing MN greater than or equal to 13 mm, obstructive jaundice, and an abrupt change in the PD caliber were predictive factors for invasive carcinoma. Systematic lymph node dissection may be omitted when a high-risk patient has none of these factors.