We present a rare case of a fistula between a pancreatic pseudocyst and the bile duct with saccular dilatation that appeared to be a type I choledocal cyst. There are only 19 described cases in the consulted bibliography. The patient was studied with an ultrasound, CT and MRCP and later surgically intervened. A resection was performed of the extrahepatic biliary and hepaticojejunostomy. There was a subsequent good evolution.

HEADINGS: Bile duct diseases. Caroli disease. Choledochal cyst. DESCRITORES: Doenças dos ductos biliares. Doença de Caroli. Cisto do colédoco.