As opposed to malignant secondary tumors, metastases of the colorectal carcinoma are benign tumors of the liver that are quite rare in the Czech Republic. From the 55 patients operated on since 2000 at our department for benign liver tumors, the most frequent are haemangiomas, focal nodular hyperplasia (FNH) and hepatocelular adenoma. Only 7.3% of them form a different histological type of a tumor than this most frequently occurring trio of tumors. The authors describe three cases of rather rare liver tumors with benign behavior that have the potential of becoming malignant. It concerns mucin producing biliary tumors, which correspond to the pancreatic intraductal papillary mucin tumor, hepatic cystadenoma with ovarian stroma and a liver hamartoma in an adult patient (Ref 13). Full Text (Free, PDF) www.bmj.sk.