A 50-year-old woman with a history of cholecystectomy 10 years ago presents with biliary colic. MRCP shows a 1.2 cm rounded filling defect in the distal common bile duct, appearing hypointense on T2-weighted images, with smooth tapering of the duct and no upstream mass. The MOST likely diagnosis is:
- A Cholangiocarcinoma
- B Ampullary carcinoma
- C Choledocholithiasis (CBD stone) ✓
- D Choledochal cyst
Correct answer: C. Choledocholithiasis (CBD stone)
Explanation
CBD stones appear as rounded filling defects on MRCP, often hypointense on T2 (especially pigment stones), with smooth meniscus-shaped or tapered margins and no associated mass. Cholangiocarcinoma shows irregular duct wall thickening or a mass. Ampullary carcinoma shows a mass at the ampulla. Choledochal cyst is a fusiform or saccular dilatation of the duct, not a filling defect within it.
Reference: Hepatobiliary Imaging (Gillian), Standard edition ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.