Intraductal papillary neoplasms and mucinous cystic neoplasms of the hepatobiliary system: demographic differences between Asian and Western populations, and comparison with pancreatic counterparts.

ABSTRACT

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 5.71 at Samsung Medical Centre in Seoul, which was significantly higher than those at the University of Washington Medical Center in Seattle (13.0) and King's College Hospital in London (16.3). 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.