Abstract
Intraductal papillary neoplasm of the bile duct (IPNB) has been described as a primary biliary neoplasm characterized by intraductal papillary growth. However, a lot of discussion have recently been made in terms of its definition and concept. Someone argues that IPNB is not a distinct entity but belongs to the spectrum of conventional bile duct cancers, while others raise the possibility that IPNB is a unique tumor possibly accounting for more than 10% of primary biliary neoplasms. Although there are various opinions, they can be categorized into three groups. In this article, I try to introduce the three major proposed standards regarding IPNB by demonstrating representative cases.
