Mucinous cystadenocarcinoma of the pancreas with mucinous biliary obstruction due to uncommon complication of fistulas to the common bile duct and main pancreatic duct.

We report a case of biliary obstruction by a large amount of mucinous material produced by a cystadenocarcinoma of the pancreas invading the common bile duct. This diagnosis was made preoperatively by various imaging methods. Endoscopic retrograde pancreatography (ERP) revealed a mucus-containing cyst with a communication to the main pancreatic and common bile ducts due to a fistulization. Mucinous biliary obstruction was observed. This case indicates that mucinous biliary obstructions should be considered in patients with a mucinous cystic neoplasm of the pancreatic head in the presence of jaundice and that mucinous cystadenocarcinoma may develop into mucinous carcinoma, especially in cases with fistula formations. ERP is useful for detecting the presence of a fistula to the common bile duct or other neighboring organs in such cases. Surgical treatment is recommended because the prognosis of mucinous cystadenocarcinoma is better than that of the usual pancreatic cancer, even though the tumor shows a communication with neighboring organs.