HISTORY AND ADMISSION FINDINGS A 75-year-old woman was admitted because of colicky upper abdominal pain. Physical examination was unremarkable. INVESTIGATIONS Alkaline phosphatase and gamma-glutamyl transpeptidase activities as well erythrocyte sedimentation rate were increased. Sonography revealed mild enlargement of the hepatocholedochal duct to 1.1 cm. Retrograde endoscopy showed a band-like immobile structure in the cystic duct. TREATMENT AND COURSE At operation the hepatocholedochal duct was found to contain a greenish mucinous mass: no cause was discovered. Three years later a tumor, 1 x 0.5 cm, was found in the common hepatic duct at sonography, with clinical signs of recurrent chronic cholitis and early liver damage. Because of hepatic dysfunction and hypersplenism no surgical intervention was undertaken. When cholestasis progressed further, a partial full-thickness resection of the hepatic duct with removal of the tumor and the mucinous bile had to be performed two years later. Histological examination revealed a villous adenoma with slight epithelial dysplasia and mucus formation. CONCLUSIONS Villous bile duct adenoma is a very rare cause of cholestasis. Mucous production can lead to mucinous bile, with resulting chronic cholecystitis and secondary biliary cirrhosis. The adenoma should be completely excised because of the danger of malignant transformation and risk of local recurrence.