Abstract
Lemmel syndrome, a rare condition, is characterized by biliary obstruction caused by a periampullary diverticulum (a pouch-like outgrowth of the duodenum near the ampulla of Vater). In our case, a 76-year-old male patient presented with epigastric pain and exhibited a cholestatic pattern on liver function tests. Imaging revealed dilated pancreatic and common bile ducts due to compression by a periampullary diverticulum (double duct sign: simultaneous dilation of the common bile duct and pancreatic duct). Upper endoscopy showed one medium-sized periampullary diverticulum. This case emphasizes the diagnostic process and the importance of considering Lemmel syndrome in differential diagnosis in elderly patients with biliary obstruction. We discuss the prevalence, diagnostic considerations, including imaging modalities, and treatment options, emphasizing the need for further research.