The Korean Journal of Hepatology 2011;17:328-330 http://dx.doi.org/10.3350/kjhep.2011.17.4.328 Liver Pathology Biliary intraepithelial neoplasia: a case with benign biliary stricture Wonkyung Jung and Baek-hui Kim Department of Pathology, Korea University Guro Hospital, Korea University College of Medicine, Seoul, Korea INTRODUCTION Intrahepatic and extrahepatic cholangiocarcinomas develops through a multistep carcinogenesis sequence and they are preceded by precursor lesions. Precursors of malignant neoplasm are identified in various organs including uterine cervix, gastrointestinal tract and breast. Identification of these precursor lesions are important in that they need minimal treatment or they are good indicator of disease progression or recurrence. In the intrahepatic and extrahepatic biliary tract, precursor lesions of malignancy are defined as follows; biliary intraepithelial neoplasia (BilIN), intraductal papillary neoplasm, mucinous cystic neoplasm, and adenoma.1 BilIN is characterized by atypical epithelial cells with multi-layering of nuclei and micropapillary projections into the lumen of bile duct.2,3 In contrast to intraductal papillary neoplasm which is characterized by papillary proliferation of epithelial cells with fibrovascular stroma and mucin production, BilIN tend to be a microscopic lesion. Mucinous cystic neoplasm is usually cystic lesions and has distinguishing clinicopathologic findings such as subepithelial stroma resembling ovarian stroma and predominant occurrence in adult female. Adenomas are commonly encountered in extrahepatic bile ducts and divided into tubular, papillary and tubulopapillary on the basis of growth pattern.1 CASE SUMMARY A 70-year-old previously healthy female presented with general weakness. She is a carrier of hepatitis B virus, but has no recent history of hepatitis. The results of a physical examination were unremarkable. Initial serum aspartate aminotransferase, alanine aminotransferase and alkaline phosphatase levels were 52 IU/L, 24 IU/L and 47 IU/L, respectively. Serologic marker for hepatitis B surface antigen was positive. Serum alpha-fetoprotein, carcinoembryonic antigen and carbohydrate antigen 19-9 levels were 2.3 ng/mL, 1.2 ng/mL and 7.1 U/mL, respectively. Abdominal ultrasono- graphy and computed tomography revealed dilatation of left intrahepatic bile ducts with focal narrowing of left hepatic duct. Because the possibility of cholangiocarcinoma could not be excluded, the patient submitted to a left lobectomy of liver. PATHOLOGIC FINDINGS On gross examination, liver surface was unremarkable. When bisected along hepatic duct, intrahepatic duct showed cystic dilatation (Fig. 1). Extrahepatic bile duct demonstrated focal narrowing of lumen, but no mass lesion was observed. Microscopically, there was wall thickening with fibrous change at extrahepatic bile duct portion. Cystically dilated intrahepatic bile duct was covered by biliary epithelia Keywords: Bile ducts; Cholangiocarcinoma; Dysplasia Abbreviations: BilIN, biliary intraepithelial neoplasia Corresponding author: Baek-hui Kim Department of Pathology, Korea University Guro Hospital, Korea University College of Medicine, 148 Gurodong-ro, Guro-gu, Seoul 152-703, Korea Tel. +82-2-2626-3255, Fax. +82-2-2626-1486, E-mail; maelstrom@naver.com Copyright Ⓒ 2011 by The Korean Association for the Study of the Liver The Korean Journal of Hepatology∙pISSN: 1738-222X eISSN: 2093-8047