3022 Metastatic Colon Adenocarcinoma Presenting as a Hilar Obstructing Lesion Diagnosed With EUS-FNB

Abstract

INTRODUCTION: Bile duct obstruction from periportal masses has a broad differential diagnosis.1 Cross-sectional abdominal imaging can help to detect periportal masses, but have low sensitivity in the diagnosis of proximal biliary and hilar lesions.2 Endoscopic ultrasound (EUS) allows for evaluation of periportal and biliary lesions and enables tissue diagnosis via fine needle biopsy (FNB). We present a case of a young patient who was presumed to have primary metastatic ovarian cancer; with EUS and ERCP guided sampling we arrived at a specific diagnosis of metastatic adenocarcinoma of colonic origin. CASE DESCRIPTION/METHODS: A 41-year-old female with a history of ovarian cancer s/p TAH and BSO and jejunal resection presented with painless jaundice, hematochezia, and high fever. Abdominopelvic CT scan showed a 2 cm mass in the region of the porta hepatis invading the portal vein and diffuse thickening of the rectosigmoid colon (Figure 1). Colonoscopy from a year prior was unremarkable, and subsequent colonoscopy was significant for hemorrhoids and hyperplastic polyps. Due to clinical suspicion for cholangitis, an ERCP was performed primarily for biliary drainage; a common hepatic duct (CHD) stricture and right hepatic duct dilation were found (Figure 2). Two 7 French 12 cm plastic stents were deployed across the common bile duct (CBD) stricture with their proximal end within the dilated right main hepatic duct. EUS showed a 2 cm lesion adjacent to the hilum that was invading the CHD and biliary bifurcation extending 1-2 cm distal and proximal to the bifurcation, portal, and hepatic artery. EUS-FNB demonstrated adenocarcinoma of jejunal origin based on cytokeratin markers (Figure 3). DISCUSSION: Specific diagnosis of periportal lesions involving the hilum of the liver is a limitation of cross-sectional imaging. EUS offers better visualization of the periportal region and enables tissue sampling for cytological or histological diagnosis. EUS-FNB has high sensitivity for diagnosis of lesions involving the common hepatic duct. It also enables assessment of vascular invasion and loco-regional staging, which is essential prior to therapy. Our case highlights, how EUS-FNB of a periportal lesion offered a specific diagnosis of metastatic colonic adenocarcinoma to the common hepatic duct. ERCP at the same session enabled biliary drainage that was essential prior to appropriate chemotherapy. The EUS FNB and ERCP with stent placement made a significant impact on the management of our patient.