Which histologic features are characteristic of primary sclerosing cholangitis?

Which histologic features are characteristic of primary sclerosing cholangitis?

• A. Granulomatous inflammation around ducts
• B. Onion-skin periductal fibrosis around bile ducts with bile duct proliferation and cholestasis
• C. Lymphocytic cholangitis without ductal changes
• D. Ductal dilation with mucin production

Answer: (B)

In primary sclerosing cholangitis, the histologic hallmark is concentric periductal fibrosis around medium to large bile ducts, producing an onion-skin appearance. This fibrous encasement narrows and can obliterate the ducts, leading to the cholestasis seen in PSC. A reactive ductular proliferation is often present as bile ducts attempt to reform in response to obstruction, accompanied by cholestasis. This combination—periductal onion-skin fibrosis with ductular reaction and cholestasis—is what distinguishes PSC on histology. Granulomatous inflammation around ducts is more typical of autoimmune cholangitis such as primary biliary cholangitis, not PSC. Lymphocytic cholangitis without ductal changes lacks the characteristic fibrotic, duct-centric pattern. Ductal dilation with mucin production suggests other processes like mucin-producing neoplasms or obstructive lesions, not the classic PSC histology.

In primary sclerosing cholangitis, the histologic hallmark is concentric periductal fibrosis around medium to large bile ducts, producing an onion-skin appearance. This fibrous encasement narrows and can obliterate the ducts, leading to the cholestasis seen in PSC. A reactive ductular proliferation is often present as bile ducts attempt to reform in response to obstruction, accompanied by cholestasis. This combination—periductal onion-skin fibrosis with ductular reaction and cholestasis—is what distinguishes PSC on histology.

Granulomatous inflammation around ducts is more typical of autoimmune cholangitis such as primary biliary cholangitis, not PSC. Lymphocytic cholangitis without ductal changes lacks the characteristic fibrotic, duct-centric pattern. Ductal dilation with mucin production suggests other processes like mucin-producing neoplasms or obstructive lesions, not the classic PSC histology.