S5254 From Pyloric Surprise to Endoscopic Success: Managing Ectopic Ampulla of Vater and Large Choledocholithiasis

Introduction: The Ampulla of Vater typically lies in the posteromedial wall of the duodenum's second part. We report a rare case of an ectopic ampulla in the pyloric canal, complicated by a 2 cm choledocholithiasis, successfully managed via endoscopic intervention. Case Description: A 65-year-old man, with no comorbidities, presented to our clinic with 5 days of abdominal pain, jaundice and 4 days of fever and chills. Labs showed total bilirubin 4.29 mg/dL, direct 2.7 mg/dL, SGOT 64 U/L, SGPT 108 U/L, ALP 188 U/L, TLC 14.83 × 109/L. Ultrasound confirmed choledocholithiasis; magnetic resonance cholangiopancreatography showed mild common bile duct (CBD) dilation and a stone. Initial endoscopic retrograde cholangiopancreatography (ERCP) with a side-viewing duodenoscope failed to locate the ampulla. A forward-viewing endoscope revealed it in the pyloric canal, facing the stomach, with 2 slit-like openings. ERCP using a colonoscope achieved CBD cannulation. Cholangiogram showed a hook-shaped, dilated CBD with a 2 cm mid-CBD stone. Sphincteroplasty to 15 mm and balloon sweeps failed to remove the stone. A plastic double-pigtail stent was placed, and the patient was discharged, advised to follow up after cholangitis improved, with plans for cholangioscopy or lithotripsy. Three weeks later, repeat ERCP post-stent removal showed a cylindrical filling defect (<1 cm diameter) in the mid-CBD. The stone was extracted via balloon with careful maneuvering, avoiding cholangioscopy or lithotripsy. He was discharged stable. Discussion: Ectopic Ampulla of Vater is rare, often in the duodenal bulb or pylorus, per limited studies. It may stem from embryogenic defects or ulcers/strictures pulling the ampulla proximally. Peng et al.’s 23-year study of 6,133 ERCP cases noted a 0.13% incidence. Saritas et al. reported 10 cases, mostly in the duodenal bulb, one in the pyloric canal, with cholangitis and hook-shaped CBD dilation common. Management used sphincteroplasty and balloons or baskets, sometimes surgery. Our case had a dilated CBD, large stone, and cholangitis. Initial ERCP failed, but stenting reshaped the stone to a cylindrical form (<1 cm), aiding removal. We hypothesize de novo stone formation in CBD due to altered mid- and distal CBD anatomy, causing bile stasis and sludge buildup. The stent likely scaffolded the soft calculus, easing extraction. Choledocholithiasis with ectopic Ampulla of Vater is rare and challenging. A colonoscope or gastroscope may suit ERCP for altered anatomy. Stenting to ease cholangitis, followed by repeat ERCP with tools like baskets or lithotripsy, can extract stones, avoiding surgery.