Incidental biliary cystadenoma mimicking liver metastasis in a gastric cancer patient.

Biliary cystadenoma represents a rare benign cystic hepatic neoplasm with premalignant potential. The diagnosis is usually difficult, and imaging methods may not be possible to clarify the pathology. It can be hard to determine, particularly in patients with a previous cancer history that has high metastatic potential in the liver. We presented a 53-year-old man with a newly diagnosed liver mass that was suspicious for metastasis 2 years after gastric cancer surgery and histological analysis confirmed the diagnosis of biliary cystadenoma.