A Rare Case of Biliary Intraepithelial Neoplasia Presenting as Biliary Stricture

Abstract

Introduction: Cholangiocarcinoma (CC) of the intrahepatic and extrahepatic biliary tree develops through a step-wise histopathological sequence that is preceded by premalignant neoplastic lesions. The two major precursors to invasive cholangiocarcinoma are biliary intraepithelial neoplasia (BilIN) and intraductal papillary neoplasm of the bile duct (IPNB). A better understanding of the mechanism of malignant transformation of biliary epithelium into CC and early identification of precursor lesions is important in order to improve long term survival. Case: A 64 year old male presented for evaluation of jaundice and generalized malaise of three weeks duration. He reported subjective weight loss and anorexia, but denied abdominal pain or diarrhea. Physical exam was remarkable for jaundice and icterus. Lab studies were significant for elevated liver chemistry consistent with obstructive cholestasis. Tumor markers, hepatitis and autoimmune profile were normal. Abdominal ultrasound and MRCP revealed intrahepatic and extrahepatic biliary ductal dilatation, with CBD measuring 9 mm at the level of the porta hepatis with abrupt narrowing and a biliary stricture and no evidence of gallstones or choledocholithiasis. Patient underwent exploratory laparotomy with cholecystectomy, common bile duct resection, Roux-en-Y hepaticojejunostomy with jejunojejunostomy. Histopathology results showed segment of bile duct with focal low-grade dysplasia (BilIN 1), and focal acute and chronic inflammation. Discussion: BilIN refers to microscopic flat or low-papillary dysplastic lesions, often seen in association with primary sclerosing cholangitis, hepatolithiasis and choledochal cysts. BilIN is further graded based upon the degree of cellular and structural atypia: BilIN-1, BilIN-2 and BilIN-3. The natural history of BilIN, its progression to invasive CC and treatment guidelines are not fully characterized. The lesions are mostly asymptomatic, unless they enlarge to cause biliary obstruction, thus making early recognition challenging. Furthermore, radiological recognition of early precancerous lesions is not feasible, unless associated with biliary stricture, as in our case. If detected early, patient can benefit from early curative surgery.Figure 1Figure 2