Clinicopathologic characteristics of intraductal papillary neoplasm of bile duct (ipnb) after central review: Korean multi-center collaboration study

Abstract

Introduction: Intraductal papillary neoplasm of the bile duct (IPNB) is a recently defined concept and its clinicopathologic characteristics and diagnostic criteria have not been well established yet. We performed this study to clarify the clinicopathologic features of IPNB and to find out the optimal morphologic criteria. Methods: Between 1997 and 2016, 457 patients were included in this study with final diagnosis of IPNB from 23 tertiary referral centers of Korea. Every case was reconfirmed through central review by 3 specialized biliary-pancreas pathologists. We applied 'Japan Biliary Association (JBA) classification' and 'modified anatomical classification' to compare the morphological features. Results: Patient's mean age was 65.5 years. The 5-year overall survival rate of all the patients was 80.6% and 104 (24.6%) patients underwent recurrence during the follow-up periods. Patients with the intestinal type (n=237; 52.2%) was the majority in the histologic subtypes of IPNB. Among 457 patients, 451 (98.7%) had bile duct dilatation and 430 (94.1%) had intraductal mass on preoperative images. We found out that the extrahepatic type had a higher rate of intestinal type and the intrahepatic type had equally high proportions of intestinal and pancreatobiliary type. Conclusion: As one of the prevalent nations of cholangiocarcinoma, this is the first Korean multi-center collaboration study of IPNB, which is thought to be a precursor lesion of cholangiocarcinoma. The 'modified anatomical classification' is a simple and intuitive criteria which can help to determine the treatment strategy and show some correlations with histologic subtype and pathologic phenotypes.