Giant duodenal diverticulum with mucinous carcinoma of distal bile duct, mimmicking Lemmel syndrome: A rare case report

INTRODUCTION: Giant duodenal diverticulum is a very rare case. There are only few cases reported. We reported a case of giant duodenal diverticulum with biliary obstruction caused by mucinous carcinoma of distal common bile duct (CBD), that mimicking Lemmel syndrome. CASE PRESENTATION: A 68-years-old man admitted to hospital with recurrent epigastric pain, jaundice and fever. Magnetic resonance cholangiopancreatography showed dilated intrahepatic and extrahepatic biliary tree, dilated gallbladder and cystic mass in pancreatic head that pushed the pancreatic duct ventrally. Emergency laparotomy was performed. Distended edematous gallbladder with necrotic spot, dilated of CBD and compressible bulging of the pancreatic head were found. Duodenotomy in 2nd-3rd part was made and found a giant duodenal diverticulum filled with food and mucus. Tight adhesion to the ampula of Vater, common bile duct, and pancreas due to fibrosis, met difficulties in dissection with a lot of bleeding, hence the diverticulum was not removed. Gastrojejunostomy, cholecystectomy and choledocho-duodenostomy were also done. Pathologic examination of CBD mucus was accordance with mucinous carcinoma. DISCUSSION: Periampullary duodenal diverticulum can cause obstructive jaundice, known as Lemmel syndrome. This case was different as the giant duodenal diverticulum located in the 3rd part filled with food and mucin that compressed both distal CBD and pancreatic duct. The cause of obstructive jaundice could be fibrotic tissue in distal CBD and mucinous carcinoma. CONCLUSION: Giant duodenal diverticulum with bile obstruction is very rare and challenging in diagnosis and treatment. The other cause of obstruction should be considered such as mucinous carcinoma of distal CBD.