Endoscopic Diagnosis and Management of Intraductal Papillary Neoplasm of Bile Duct (IPNB)

Abstract

Introduction: A 76-year-old man with hypertension presented with a 3-week history of progressive painless jaundice. Three weeks prior to presentation the patient noticed his urine turned tea colored and he developed itching all over. Lab testing revealed an alkaline phosphatase level of 1264 U/L, ALT 252 U/L, AST 161 U/L, total bilirubin 11.6 mg/dL, and direct bilirubin 10.9 mg/dL. Abdominal CT scan showed a marked dilatation of the left intrahepatic bile ducts. A normal extrahepatic bile duct which returns to normal caliber after the hepatic duct bifurcation was noted. No pancreatic ductal dilatation was seen. ERCP was performed. The CBD was cannulated and sphincterotomy was done. The biliary tree was swept with an extraction balloon starting at the hepatic duct bifurcation. Multiple biliary stones causing a partial obstruction were removed. Additional sweeps of the duct removed a large amount of tissue. Histopathological examination identified this tissue as a well differentiated, invasive adenocarcinoma. He chose not to have any surgical treatment and since no lymphnode/perineural invasion is present, he was started on stereotactic body radiotherapy and is followed up regularly. IPNB is an uncommon tumor of the bile duct characterized by an intraductal growth and is considered as a biliary counterpart of the intraductal papillary mucinous neoplasm (IPMN) of the pancreas. IPNB can develop in the intrahepatic, hilar, and extrahepatic regions of the bile duct. Histologically they are characterized by the prominent papillary growth of atypical biliary epithelium with distinct fibrovascular cores. The common clinical signs of IPNB are abdominal pain, jaundice, and/or cholangitis. Radiological imaging studies commonly indicate diffuse bile duct dilatation with/without a papillary mass. IPNB is histologically categorized into 4 types: pancreatobiliary, intestinal, gastric, and oncocytic. Pancreatobiliary and intestinal type are more common compared to gastric and oncocytic type. Mucin secretion is more frequent with the intestinal type than the pancreatobiliary type. More than half of all IPNBs contain carcinoma components, and the pancreatobiliary type is more commonly associated with invasive carcinoma than the gastric and intestinal types. The management of IPNB includes surgical resection and can include chemoradiation therapy if invasive carcinoma is confirmed. IPNBs have a better outcome compared to nonpapillary bile duct carcinomas.