Intraductal papillary mucinous neoplasm of the bile duct with choledochoduodenal fistula: a case report and literature review.

Background: Intraductal papillary mucinous neoplasm of the bile duct (IPMN-B) is a neoplastic disease of the bile duct with papillary hyperplasia and mucus secretion, which originates from the duct epithelium and rarely complicates with fistula formation.

Case description: The patient was admitted to the hospital due to abdominal pain and yellow skin. Laboratory results showed alanine aminotransferase 299 U/L, total bilirubin 350 µmol/L, computerized tomography showed severe dilatation of common bile duct and extrahepatic bile duct. Magnetic resonance cholangiopancreatography showed the intra- and extrahepatic bile ducts were markedly dilated, and the signal of the bile ducts was uneven. Endoscope identified a large amount of mucus above the papilla that flowing out from the fistula. Further cholangiography through the fistula showed significant dilatation of the extrahepatic bile duct. SpyGlass examination showed a large amount of gelatinous mucus in the bile duct lumen and "fish-scaly or coral" changes in the mucosa of the right anterior branch bile duct, hepatic hilum as well as lower common bile duct. IPMN-B with choledochoduodenal fistula was diagnosed. The patient was then discharged with nasal biliary drainage and biliary stenting, oral antipyretic and hepatoprotective drugs. The patient's biliary obstruction and symptoms of infection improved with medical treatment but recured. Unfortunately, the patient died 10 months after his first visit.

Conclusions: SpyGlass has advantages in identifying the nature and extent of lesions, providing important references for diagnosis and treatment. Endoscopic intervention relieves biliary obstruction to some extent in patients with high operative risk or reluctance to undergo surgery.