Background:Surgical resection is generally considered the main curative treatment for intrahepatic biliary cystadenocarcinoma (IBCA) or suspected IBCAs,but controversy exists regarding the prognosis for IBCAs.This study aimed to describe the clinicopathological characteristics of IBCA and identify prognostic factors that may influence the survival of patients treated with surgical procedures.Methods:Thirty-four patients with histologically confirmed IBCA treated between January 2000 and June 2014 were included.The clinical characteristics of patients with IBCA were compared with those of 41 patients with intrahepatic biliary cystadenoma (IBC);factors that significant difference were analyzed for prognosis analysis of IBCA using multivariate/univariate Cox proportional hazards regression models.Survival curves were constructed using the Kaplan-Meier method and compared using the log-rank test.Results:IBCAs had a strong female predominance,and the most common presenting symptoms were abdominal pain or discomfort.Compared with IBCs,IBCAs occurred in older patients,in more male patients,and were associated statistically significant abnormal increase in alanine aminotransferase (P =0.01) and total bilirubin (P =0.04).Mural nodules were more frequently seen with IBCAs and may associate with malignancy.It was difficult to differentiate between IBC and IBCA based on laboratory examination and imaging findings.Although complete resection is recommended,enucleation with negative margins also achieved good outcomes.Median overall patient survival was 76.2 months;survival at 1,3,and 5 years was 88.0％,68.7％,and 45.8％,respectively.Radical resection and noninvasive tumor type were independent prognostic factors for overall survival.Conclusions:It remains difficult to distinguish between cystadenomas and cystadenocarcinomas based on laboratory examination and image findings.Complete resection is recommended for curative treatment,and patients should be closely followed postoperatively,particularly those with invasive tumors.