A 50-year-old woman with primary sclerosing cholangitis (PSC) has a 'beaded' bile duct pattern on ERCP. The pathognomonic histological finding on liver biopsy is:

• A Florid duct lesion — granulomatous destruction of interlobular bile ducts
• B Centrilobular necrosis with cholestasis
• C Portal lymphocytic infiltration with plasma cells
• D Periductal 'onion-skin' fibrosis around medium and large bile ducts ✓

Explanation

PSC is characterized by concentric periductal fibrosis ('onion-skin' fibrosis) around medium and large bile ducts, causing progressive stricturing and dilatation — the beaded cholangiographic appearance. This eventually leads to obliterative fibrous cholangitis and biliary cirrhosis. Florid duct lesion (granulomatous bile duct destruction) is pathognomonic of primary biliary cholangitis (PBC), not PSC. Plasma cell–rich portal infiltrate is autoimmune hepatitis.

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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