Lemmel's Syndrome: A Rare Cause of Obstructive Jaundice Due to Periampullary Duodenal Diverticulum.

Lemmel's syndrome is a rare cause of obstructive jaundice resulting from extrinsic compression of the distal common bile duct by a periampullary duodenal diverticulum. Its clinical presentation often mimics more common etiologies, such as choledocholithiasis or malignancy, leading to frequent underdiagnosis. We report a case of a 72-year-old man who presented with progressive jaundice, dark urine, and mild right upper quadrant discomfort. Laboratory tests revealed elevated total bilirubin and cholestatic liver enzymes, with normal inflammatory markers. Imaging studies, including abdominal ultrasound, contrast-enhanced computed tomography, and magnetic resonance cholangiopancreatography (MRCP), demonstrated biliary dilatation and a gas- and fluid-filled periampullary diverticulum compressing the distal common bile duct, without evidence of stones or masses. Endoscopic retrograde cholangiopancreatography (ERCP) confirmed the diagnosis and allowed therapeutic intervention through sphincterotomy and temporary biliary stenting. The patient's jaundice resolved completely, liver function tests normalized, and he remained asymptomatic during a six-month follow-up period. Lemmel's syndrome should be considered in elderly patients presenting with obstructive jaundice in the absence of choledocholithiasis or malignancy. Prompt recognition through appropriate imaging and endoscopic management ensures excellent outcomes and prevents unnecessary surgical procedures.