Impact of Tumor Location on Postoperative Outcome of Intraductal Papillary Neoplasm of the Bile Duct

Background The concept of intraductal papillary neoplasm of the bile duct (IPNB) has been proposed to be the biliary equivalent of intraductal papillary mucinous neoplasm (IPMN) of the pancreas. While the classification of IPMNs is based on their location of duct involvement, such classification has not been fully evaluated for IPNBs. The aim of this study is to investigate the value of IPNB classification based on its location. Methods A total of 306 consecutive patients who underwent surgical resection with a diagnosis of bile duct tumor were enrolled. Among these patients, 21 were diagnosed as having IPNB. The IPNBs were classified into two groups as follows: extrahepatic IPNB, which located in the distal or perihilar bile duct, and intrahepatic IPNB, which located more peripherally than the hilar bile duct. The clinicopathological features of the two groups were then compared. Results Extrahepatic IPNB tended to show more invasive characteristics than intrahepatic IPNB (presence of invasive component: 40.0 vs. 9.1%, p = 0.084). Moreover, patients with extrahepatic IPNB showed significantly poorer relapse-free survival (RFS) than those with intrahepatic IPNB [5-year RFS rate (%): 81.8 vs. 16.2, p = 0.014]. Conclusion Patients with intrahepatic IPNB show more favorable pathological characteristics and postoperative survival outcomes than those with extrahepatic IPNB.