The intrahepatic biliary cystadenoma is a rare benign tumor of the liver, originating from an intrahepatic bile duct: it becomes symptomatic only when it causes obstruction of the bile duct itself. Regardless of the various diagnostic modalities available, it is difficult to distinguish preoperatively the cystadenoma both from a simple liver cyst, and from a cystic carcinoma of the bile duct. An incomplete surgical removal of the cyst often results in a higher risk of size increase and recurrence, even considering that the lesion may degenerate into a cystadenocarcinoma. Between January 2004 and May 2011, 1,173 liver resections were carried out at the Hepatobiliary Surgery Unit of San Raffaele Hospital: 12 of these were performed for cystadenoma. Forty-six patients underwent laparoscopic liver cysts deroofing: definitive histological examination in six of these patients revealed instead the diagnosis of cystadenoma. In 50% of cases, the diagnosis of cystadenoma was therefore acquired as a result of an incidental finding. The patients were all female, median age 45 years. The liver resection included six cases of left hepatectomy, three left lobectomies, and three of the right hepatectomy. The operations were performed by laparotomy, with the exception of two left lobectomies completed laparoscopically. In all cases, the postoperative course was without major complications. The resection was radical in all cases and the median hospital stay was 5 days. At a median follow-up of 16 months (range 7-30), all patients are alive and disease free. Biliary cystadenomas can easily be misunderstood and interpreted as simple hepatic cysts. Radical surgical resection is necessary and provides good short- and long-term outcomes.