Clinicopathological features and prognosis of mucin‐producing bile duct tumor and mucinous cystic tumor of the liver: a multi‐institutional study by the J apan B iliary A ssociation

Background The aim of this study was to determine the clinicopathological features and surgical outcomes of mucinous cystic neoplasm of the liver ( MCN ) and mucin‐producing intraductal papillary neoplasm of the intrahepatic bile duct ( M ‐ IPNB ). Methods We performed a multi‐institutional, retrospective study of patients with MCN or M ‐ IPNB pathologically defined by the presence or absence of an ovarian‐like stroma. Results The M ‐ IPNB and MCN were diagnosed in 119 and nine patients, respectively. MCN was observed in female patients, while M ‐ IPNB produced symptoms of cholangitis. M ‐ IPNBs were classed as low or intermediate grade in 53 cases, high grade in 23 and invasive carcinoma in 43. Fifty‐one of the M ‐ IPNBs were the pancreatobiliary type ( PT ), 33 were the intestinal type ( IT ), 23 were the oncocytic type ( OT ), and 12 were the gastric type ( GT ). The 1‐, 5‐ and 10‐year survival rates for the 105 patients with M ‐ IPNB were 96%, 84% and 81%, respectively, while the 5‐year survival rate for patients with MCN was 100%. OT and GT M ‐ IPNB had better 10‐year survival rates than PT and IT M ‐ IPNB . Conclusions Although MCN has different features from M ‐ IPNB , both diseases have a good prognosis after resection. The cellular type of M ‐ IPNB appears to predict outcome.