Lemmel Syndrome Mimicking Choledocholithiasis: A Rare Cause of Obstructive Jaundice

Abstract

Lemmel syndrome is a rare but clinically important cause of obstructive jaundice, arising from external compression of the common bile duct (CBD) by a periampullary duodenal diverticulum, typically in the absence of choledocholithiasis or underlying malignancy. Although infrequently encountered in clinical practice, it represents a significant differential diagnosis in patients presenting with cholestatic liver function abnormalities and evidence of biliary obstruction where no definitive obstructing lesion is identified on routine evaluation. We report the case of a 60-year-old Malay woman who presented with right hypochondriac pain associated with cholestatic features. Initial clinical assessment raised suspicion of biliary obstruction secondary to biliary sludge or choledocholithiasis. However, further evaluation with contrast-enhanced computed tomography (CT), endoscopic ultrasound (EUS), and magnetic resonance cholangiopancreatography (MRCP) demonstrated extrinsic compression of the distal CBD by a periampullary duodenal diverticulum, consistent with Lemmel syndrome. The patient was managed conservatively and showed clinical improvement without the need for surgical intervention. This case highlights the importance of considering Lemmel syndrome as a potential cause of obstructive jaundice, particularly when common etiologies such as biliary stones or malignancy are absent. It also emphasizes the valuable role of advanced imaging modalities, including CT, EUS, and MRCP, in establishing an accurate diagnosis and guiding suitable management.