Abstract
A giant common bile duct (CBD) calculus is a rare occurrence, and the presence of a giant calculus within a choledochal cyst (CDC) is even more unusual. In this case report, we detail an instance of a giant CBD calculus measuring 7 cm x 3 cm found within a CDC, accompanied by multiple tiny calculi. Magnetic resonance cholangiopancreatography (MRCP) revealed the dilation of the bi-lobar intrahepatic biliary radical (IHBR) and the CBD. A large T2 hypointense and T1 hyperintense calculus occupied the dilated CBD and common hepatic duct (CHD), extending into the left hepatic duct (LHD) and right hepatic duct (RHD). There was a possibility of type 1c CDC with cystolithiasis, hepatolithiasis, and cholelithiasis. The patient underwent open cholecystectomy with choledochotomy, stone retrieval, excision of the CDC, and Roux-en-Y hepaticojejunostomy.