摘要Background:Biliary mucinous cystic neoplasms(BMCNs)are rare hepatobiliary cystic tumors,which can be divided into noninvasive and invasive types.This study aimed to investigate the diagnosis,treatment,and prognosis of BMCNs in a large single center.Methods:We analyzed 49 patients with BMCNs confirmed by postoperative pathology at the First Affili-ated Hospital,Zhejiang University School of Medicine between January 2007 and December 2021.Results:Among the 49 patients,37 were female(75.5％),and the average age was 57.04 years.Common symptoms included abdominal discomfort,jaundice and fever,while 22 patients(44.9％)had no symp-toms.Serum carbohydrate antigen(CA)19-9 and CA125 concentrations were elevated in 34.8％and 19.6％of patients,respectively.Forty-eight patients had tumors in the intrahepatic bile ducts and only one had a tumor in the extrahepatic bile duct.Forty-eight patients with noninvasive intrahepatic BMCNs were further analyzed in terms of pathological features:34(70.8％)had low-grade intraepithelial neoplasms(LGINs),and 14(29.2％)had high-grade intraepithelial neoplasms(HGINs).The potential immunohisto-chemical markers of BMCNs were cytokeratin(CK)19,CK7,estrogen receptor and progesterone receptor.Follow-up data for 37 patients with intrahepatic BMCNs were obtained.The median overall survival(OS)of BMCNs was not reached.The longest survival time was 137 months.The 5-and 10-year OS rates were 100％and 85.4％,respectively.The 5-and 10-year recurrence-free survival(RFS)rates were 93.9％and 80.2％,respectively.Conclusions:BMCNs are rare cystic neoplasms that commonly occur in middle-aged females.BMCNs can only be diagnosed and classified by postoperative pathology,as there are no specific clinical presenta-tions,serological indicators or imaging modalities for preoperative diagnosis.Complete surgical resection is necessary for BMCNs,and the postoperative prognosis is favorable.