An Unexpected Outcome Following Radiofrequency Ablation of a Malignant Biliary Stricture

Abstract

A 60-year-old woman with extrahepatic cholangiocarcinoma and recurrent malignant biliary strictures status-post placement of two overlapping distal bile duct uncovered self-expandable metal stent (SEMS) presented with fevers, pruritis, and abdominal pain. Laboratory findings revealed a total bilirubin of 4.2 mg/dL and alkaline phosphatase of 920 U/L. Endoscopic retrograde cholangiopancreatography (ERCP) demonstrated stenosis in the common bile duct (CBD) due to tumor/tissue ingrowth through prior SEMS (Image A). Tumor/tissue destruction was performed with radiofrequency ablation (RFA) using the HabibTM EndoHPB Probe. Intrabiliary RFA was applied to the stenosis (ERBE generator, bipolar soft coag 10 watts) for 90 seconds. Two sequential applications were applied to the length of the stricture. Immediately following RFA, the periampullary mucosa was noted to be pale (Images B, C). A double pigtail plastic biliary stent was placed in the left hepatic duct. Overnight she developed epigastric pain with a lipase of 923 U/L. Her mild acute pancreatitis was managed conservatively and she was discharged on post-ERCP day 4; plastic stents were removed after two months. She returned eight weeks later with recurrent cholangitis. ERCP revealed an intra-stent biliary stricture in the mid-CBD. Two intraductal RFA applications were performed without mucosal changes, and a covered SEMS was placed. She later developed epigastric pain with elevated lipase; again with documented evidence of post-RFA acute pancreatitis. She was successfully treated conservatively. In the absence of other identifiable causes, our hypothesis is that acute pancreatitis was caused by thermal burn injury from RFA, representing the first confirmed case due to its recurrent nature. In malignant biliary obstruction with stent placement, RFA causes coagulative necrosis of tumor tissue to prevent tumor ingrowth and epithelial hyperplasia, improving biliary stent patency. A literature review of RFA through SEMS for biliary tissue/tumor ingrowth reveals no reported cases of thermal burn injury causing acute pancreatitis. In two single center studies, one patient developed mild pancreatitis after RFA but without endoscopic evidence of thermal burn injury; another patient developed asymptomatic amylase elevation. As RFA through SEMS becomes more widely used, thermal burn injury-induced acute pancreatitis represents a potential adverse event, and represents another specific etiology for acute pancreatitis.Figure: Tumor/tissue ingrowth of SEMS.Figure: Pale peri-ampullary mucosa.Figure: Closer view of pale peri-ampullary mucosa.