Objective To summarize the diagnosis and treatment experiences of intrahepatic biliary cystadenoma and cystadenocarcinoma and the factors affecting prognosis of patients. Methods The clinical data of 46 patients with cystadenoma and 19 patients with cystadenocarcinoma who were admitted to the Eastern Hepatobiliary Surgery Hospital from January 2001 to December 2012 were retrospectively analyzed. All the patients underwent B-ultrasound, computed tomography (CT) and magnetic resonance imaging (MRI) examinations, and received the resection of liver by the Pringle maneuver or without hepatic inflow occlusion, and then the prognoses of patients was analyzed. All the patients were followed up via telephone interview and correspondence up to April 2013. The measurement data with normal distribution were presented as ±s. The survival curve was drawn by Kaplan-Meier method and survival analysis was done using the Log-rank test. The univariate analysis and multivariate analysis were done using the chi-square test and COX regression model. Results (1) The results of B ultrasound, CT and MRI showed that the imaging features of cystadenoma and cystadenocarcinoma were very similar, which included papilla on the cystic wall, obvious thickening of cystic wall and multilocular cystic spaces. Before operation, cystadenoma was confirmed in 20 patients and cystadenocarcinoma in 7 patients by imaging examinations. (2) Forty-six patients with intrahepatic biliary cystadenoma underwent surgical treatment, including 22 with local tumor enucleation, 15 with left lobectomy, 3 with external lobectomy, 4 with right hemihepatectomy, 1 with right posterior lobectomy and 1 with right anterior lobectomy. There were 38 patients with the vascular inflow occlusion by the Pringle maneuver and 8 without vascular inflow occlusion. The operation time and mean volume of blood loss were (175 ±70) minutes and 300 mL (range, 200-400 mL) . There were 4 patients with bile leakage, 3 with rebleeding and 2 with liver dysfunction, and they got full recovery by conservative treatment. Among 19 patients with intrahepatic biliary cystadenocarcinoma, 9 received local tumor enucleation, 8 received left lobectomy, 1 received left external lobectomy and 1 received right posterior lobectomy. There were 13 patients with vascular inflow occlusion by the Pringle maneuver and 6 without vascular inflow occlusion. The operation time and volume of blood loss were (210 ±68) minutes and 500 mL (range, 200-800 mL) . After operation, the bile leak-age was detected in 3 patients, rebleeding in 2 patients and liver dysfunction in 1 patient, and the conditions of patients were improved by conservative treatment. The results of postoperative pathological examinations showed that intrahepatic biliary cystadenoma was arranged-irreguarly simple columnar epithelium without cytologic atypia in the cystic spaces and intrahepatic biliary cystadenocarcinoma was papilla with cytologic atypia and basement membrane infiltration in the cystic spaces. (3) Fifty-seven patients were followed up for 14-139 months and 8 were lost to follow-up (5 with cystadenoma and 3 with cystadenocarcinoma) . During the follow-up, 2 patients had recurrence of intrahepatic biliary cystadenoma, and 1 of whom died of postoperative liver dysfunction. Among 13 patients with recurrence of intrahepatic biliary cystadenocarcinoma, 10 died and including 1 with canceration of cystadenoma. (4) The 1-, 3-, 5-year survival rates of the patients with intrahepatic biliary cystadenoma and cystadenocarcinoma were 98% , 98% , 98% and 88% , 31% , 13% , respectively. CA19-9 was a risk factor affecting the tumor-free survival rate and overall survival rate in patients with intrahepatic biliary cystadenocarcinoma by the univariate analysis (χ2=8. 540, 4. 946, P <0.05) . The high level of CA19-9 was an independent risk factor affecting the tumor free survival rate and overall survival rate in patients with intrahepatic biliary cystadenocarcinoma by the multivariate analysis (OR =8. 239, 5. 365, 95% confidence interval: 1. 664-40. 800, 1. 022-28. 172, P < 0.05) . Conclusions The clinical symptoms of intrahepatic biliary cystadenoma and cystadenocarcinoma are atypical. Imaging examination can help improve to preoperative evaluation with the low coincidence rate. The surgical resection is a main treatment method. CA19-9 is an important index for evaluating the prognosis of patients with intrahepatic biliary cystadenocarcinoma. Key words: Liver neoplasms; Cystadenoma; Cystadenocarcinoma; CA19-9