A 48-year-old woman presents with intermittent right upper quadrant pain and mild jaundice. MRCP shows a large calculus impacted at the neck of the gallbladder producing smooth extrinsic compression of the common hepatic duct. The intrahepatic ducts are dilated, the distal common bile duct is normal calibre, and there is no intraductal filling defect. Which is the most likely diagnosis?

• A Klatskin tumour
• B Mirizzi syndrome ✓
• C Choledocholithiasis
• D Primary sclerosing cholangitis

Explanation

Mirizzi syndrome is mechanical obstruction of the common hepatic duct by a stone impacted in the cystic duct or Hartmann pouch, producing smooth extrinsic compression rather than an intraluminal defect. The distal CBD remains normal because the obstruction sits above it. Choledocholithiasis would show a filling defect within the duct itself, while a Klatskin tumour gives an irregular abrupt stricture at the confluence, not a smoothly compressed duct adjacent to an impacted gallbladder stone.

Reference: Grainger and Allison's Diagnostic Radiology, 7th ed.

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Written and medically reviewed by the StethoPrep medical team.