Lemmel Syndrome Causing Distal Common Bile Duct Obstruction: A Case Report

Background: Lemmel syndrome is an uncommon cause of distal common bile duct (CBD) obstruction associated with a periampullary duodenal diverticulum in the absence of bile duct calculi or an obstructing neoplasm. Recognition may be difficult when jaundice is absent. Case Presentation: A 66-year-old woman with diabetes mellitus, hypertension and dyslipidaemia, who was receiving aspirin and had undergone cholecystectomy 18 years previously, presented with recurrent burning right upper quadrant abdominal pain. She reported no vomiting, fever, pruritus, jaundice or altered bowel habits. Abdominal computed tomography (CT) revealed a large periampullary duodenal diverticulum containing faecalised enteric material and causing extrinsic compression of the distal CBD/ampullary region. Marked CBD dilatation and minimal central intrahepatic biliary dilatation were noted. Endoscopic ultrasound (EUS) showed a CBD diameter of 1.3 cm and demonstrated its distal course towards the diverticulum. No biliary calculi or obstructing lesions were identified. The pancreas appeared normal, without calcifications or pancreatic duct dilatation, and no significant lymphadenopathy was identified. Side-viewing endoscopy confirmed the periampullary diverticulum. Endoscopic retrograde cholangiopancreatography (ERCP) was subsequently performed, and a biliary stent was placed. The patient's right upper quadrant pain improved following stenting. Conclusion: This case illustrates the importance of considering Lemmel syndrome when unexplained CBD dilatation accompanies a periampullary diverticulum, even without clinically apparent jaundice. CT, EUS and side-viewing endoscopy provided complementary diagnostic information, while ERCP enabled biliary stenting and was followed by symptomatic improvement.