Intraductal papillary neoplasms and mucinous cystic neoplasms of the hepatobiliary system: demographic differences between A sian and W estern populations, and comparison with pancreatic counterparts

AIMS: To improve the characterization of intraductal papillary neoplasm of the bile duct (IPNB) and mucinous cystic neoplasm of the liver (MCN-L). METHODS AND RESULTS: A retrospective review of pathology archives (1999-2011) in our three institutions identified cases of IPNB (n = 138) and MCN-L (n = 54). The IPNB/MCN-L ratio was 5.7:1 at Samsung Medical Centre in Seoul, which was significantly higher than those at the University of Washington Medical Center in Seattle (1:3.0) and King's College Hospital in London (1:6.3). This difference was mainly attributable to the considerably larger number of patients with IPNB in Seoul (n = 131) than in Seattle and London (n = 7). Western patients with IPNB were all non-Asian in ancestry. IPNB differed from pancreatic intraductal papillary neoplasm in its higher histological grade, more advanced stage of an associated invasive cancer, and worse prognosis. In contrast, MCN-L showed significantly lower histological grade than its pancreatic counterpart (P = 0.022). Unlike in pancreatic mucinous cystic neoplasm, malignant transformation was very rare in MCN-L (10% versus 2%). CONCLUSIONS: This study demonstrated demographic differences in IPNB and MCN-L among regions. IPNB and MCN-L differ from their pancreatic counterparts in the risk of malignant transformation and patients' prognosis.