S3387 Lemmel Syndrome: An Unusual Case of Biliary Obstruction in the Setting of COVID-19 Infection

Introduction: Lemmel syndrome is a rare and intriguing cause of obstructive jaundice, most commonly associated with a periampullary duodenal diverticulum (PDD). This syndrome presents a diagnostic challenge due to the often subtle or overlapping features with other more common causes of biliary obstruction. In this case report, we discuss the diagnosis and management of Lemmel syndrome in a 68-year-old man who presented with acute abdominal symptoms in the setting of coronavirus disease 2019 (COVID-19) infection. Case Description/Methods: A 68-year-old man presented with a sudden, acute onset of diffuse epigastric abdominal pain, nausea, and vomiting. Notably, the patient had recently tested positive for COVID-19. Vital signs were stable. On physical examination, the patient was found to have generalized tenderness with mild guarding. Laboratory investigations revealed mild leukocytosis with a bandemia, suggesting an inflammatory process or infection. Liver function tests were abnormal, with elevated bilirubin and alkaline phosphatase, raising concern for biliary obstruction. Right upper quadrant ultrasound revealed a distended gallbladder with sludge and evidence of intrahepatic biliary dilatation, consistent with obstructive jaundice. A contrast-enhanced computed tomography scan of the abdomen and pelvis demonstrated a distended gallbladder with a moderate intrahepatic biliary dilatation and a common bile duct diameter of 20 mm with abrupt cut-off near the ampulla. In addition, the computed tomography images revealed an unusual finding—a small periampullary duodenal diverticulum (PDD) near the ampulla of Vater, located close to the common bile duct (CBD) and pancreatic duct. This raised suspicion for Lemmel syndrome, a condition in which the PDD causes extrinsic compression of the bile and/or pancreatic ducts, leading to biliary obstruction. Magnetic resonance cholangiopancreatography also revealed a dilated common bile duct to the level of the ampulla and a large periampullary duodenal diverticulum. Discussion: Lemmel syndrome is a rare but important cause of obstructive jaundice that can be difficult to diagnose due to its nonspecific presentation. This case illustrates the importance of considering Lemmel syndrome in patients with biliary obstruction who have a periampullary duodenal diverticulum, as early recognition can guide appropriate management and avoid unnecessary procedures. Proper imaging is key to identifying this rare condition and distinguishing it from more common causes of jaundice.