Congenital bile duct cysts are well-documented anomalies of the biliary tree. Choledochal cysts frequently caused malignant changes in the epithelial lining. In such patients, the prognosis is very poor, mainly because of the variety of detection results at the early stage. We report a 77-year-old woman who was referred to our hospital due to jaundice. In this patient, choledochal cysts were detected by cholangioscopy, and in the further course a carcinoma within the papillae was found. As the patient refused an operation, endoscopic treatment had to be performed. After repeated unsactisfactory attempts with plastic stents, an excellent outcome could be achieved using a metal stent. The maintance of carcinoma in patients with bile duct cysts is estimated at 2.5-15%, compared to an incidence of 0.012-0.48% in patients without bile duct cysts. Due to the rarity of bile duct cysts, there are no data available concerning the implantation of meta I stents. The 5-year survival rate is virtually 0%.