LAUSR

A 69-year-old woman was evaluated in a local Emergency Department with a 2-week history of worsening abdominal discomfort, decreased appetite, vomiting, jaundice, and dark urine. Her total bilirubin at that time was 7.0. An abdominal ultrasound revealed mild bilateral intrahepatic biliary ductal dilation and a heterogeneous hyperechoic lesion in the left hepatic duct. A computed tomography (CT) scan was notable for intrahepatic biliary dilatation, greater in the left lateral segment (Fig. 1). She subsequently underwent magnetic resonance imaging (MRI) which revealed leftsided intrahepatic biliary ductal dilation, abruptly terminating at the location of a lesion in the left lobe of the liver. Endoscopic retrograde cholangiopancreatography (ERCP) and biliary stenting were performed. Endoscopic ultrasound documented a 3 × 2 cm mass in the common hepatic duct; fine-needle aspiration was interpreted as consistent with adenocarcinoma. Tumor markers revealed carcinoembryonic antigen (CEA) of 1 and CA 19-9 of 256. She was taken to the operating room for a left hepatic tri-segmentectomy with caudate lobectomy, Roux-en-Y hepatico-jejunostomy, as well as porta hepatis and celiac lymphadenectomy. Intraoperative findings were consistent with a tumor involving the entire left biliary system, left hepatic duct, and extending into the common hepatic duct. Gross examination of the specimen revealed a cylindrical, firm mass residing within and encased by the bile duct. The tumor was centered in the left intrahepatic biliary tree but extended into the hepatic duct, approximately 3.2 cm from the distal common bile duct margin (Fig. 2). It also extended superiorly into the liver, extending out into peripheral bile ducts. Conforming to the shape of the biliary tree, the tumor was measured at > 6 cm in maximal dimension. Since the majority of the tumor was easily separated from the adjacent duct wall, it was initially difficult to identify any base or area of adherence. Only on subsequent submission of the entire left intrahepatic biliary tree was the origin of the tumor identified. The hepatic parenchyma was uninvolved, and the tumor was free of the bile duct resection margin. Histologic examination revealed an epithelial neoplasm consisting of cells characterized architecturally by a striking tubular arrangement (Fig. 3). The tubules were of varying density, with some areas of tumor showing a dense arrangement giving rise to a cribriform-type architecture. In scattered foci, the neoplastic epithelium lost its tubular arrangement entirely, adopting a microscopically solid growth pattern. No papillary structures were identified. There was no histologic evidence of mucinous differentiation. The biliary epithelium adjacent to the tumor was microscopically uninvolved revealing no morphologic features of dysplasia. Histologic sections of the portion of tumor adherent to the neighboring left hepatic duct wall were distinct; here, overlying tumor that irregularly displaced the underlying stroma obliterated the native biliary epithelium. The stroma in this area was uniquely characterized by a conspicuous inflammatory response, heralding the presence of irregularly shaped, infiltrative tubules of neoplastic epithelium that invaded the duct wall and subjacent hepatic parenchyma spanning an area of 0.6 cm. There was no lymphovascular or perineural invasion; the invasive component was widely free of the resection margins. Four porta hepatis and celiac lymph nodes showed no evidence of carcinoma. Taken together, the gross and microscopic findings were diagnostic of a * Brendan C. Visser [email protected]