Published online Apr 21, 2021. doi: 10.3748/wjg.v27.i15.1569
Peer-review started: January 17, 2021
First decision: February 9, 2021
Revised: February 13, 2021
Accepted: March 24, 2021
Article in press: March 24, 2021
Published online: April 21, 2021
Processing time: 87 Days and 0.7 Hours
Bile duct epithelial tumours showing papillary neoplasm in the bile duct lumen are present in the intrahepatic and extrahepatic bile ducts. Clinicopathological images of these tumours are distinctive and diverse, including histological images with a low to high grade dysplasia, infiltrating and noninfiltrating characteristics, excessive mucus production, and similarity to intraductal papillary mucinous neoplasm (IPMN) of the pancreas. The World Health Organization Classification of Tumours of the Digestive System in 2010 named these features, intraductal papillary neoplasm of the bile duct (IPNB), as precancerous lesion of biliary carcinoma. IPNB is currently classified into type 1 that is similar to IPMN, and type 2 that is not similar to IPMN. Many of IPNB spreads superficially, and diagnosis with cholangioscopy is considered mandatory to identify accurate localization and progression. Prognosis of IPNB is said to be better than normal bile duct cancer.
Core Tip: Intraductal papillary neoplasm of the bile duct (IPNB) is classified into type 1 that is similar to intraductal papillary mucinous neoplasm (IPMN) and type 2 that is not similar to IPMN. Many of IPNB spreads superficially, and diagnosis with cholangioscopy is considered mandatory to identify accurate localization and progression. Prognosis of IPNB is said to be better than normal bile duct cancer.