Primary sclerosing cholangitis
- Lesion
In primary sclerosing cholangitis scar narrows the large and medium bile ducts; it is linked to ulcerative colitis and to bile duct cancer.
What it is
Primary sclerosing cholangitis is a chronic cholestatic disease with inflammation and concentric fibrosis of intrahepatic and extrahepatic bile ducts, giving alternating strictures and dilations. It is more common in men, often linked to inflammatory bowel disease (mainly ulcerative colitis), and carries a high risk of cholangiocarcinoma. Its cause is unknown; immune mechanisms and gut-derived signals are suspected. It must be told apart from IgG4-related sclerosing cholangitis, which responds to corticosteroids.
Structure
- Large ducts: thickened fibrotic walls with chronic inflammation; strictures alternating with dilated segments.
- Small ducts: concentric onion-skin fibrosis around atrophic ducts, then replacement by a solid cord of scar.
- End stage: biliary cirrhosis.
Step by step
- Genetic susceptibility (HLA associations) and gut-derived signals in IBD are thought to start biliary inflammation.
- T cells homing from the gut and inflamed bile ducts damage cholangiocytes.
- Periductal fibroblasts lay concentric collagen: onion-skin fibrosis.
- Ducts narrow and are replaced by scar; bile stagnates upstream.
- Chronic cholestasis and recurrent cholangitis lead to biliary cirrhosis; dysplasia may lead to cholangiocarcinoma.
Primary biliary vs primary sclerosing cholangitis
| Feature | Primary biliary cholangitis | Primary sclerosing cholangitis |
|---|---|---|
| Sex and age | Mostly women, middle age | Mostly men, often younger |
| Ducts affected | Small intrahepatic interlobular ducts | Large and medium intrahepatic and extrahepatic ducts |
| Key lesion | Florid duct lesion, granulomas | Onion-skin periductal fibrosis, fibro-obliterative scars |
| Serology | Antimitochondrial antibodies | Atypical p-ANCA; no specific antibody |
| Associations | Sjögren, systemic sclerosis, thyroiditis | Ulcerative colitis, pancreatitis |
| Imaging | Normal large ducts | Beaded strictures on cholangiography |
| Cancer risk | HCC once cirrhotic | Cholangiocarcinoma; colorectal cancer with colitis |
Test yourself
Think of the answer, then tap the question to see it.
What is the classic cholangiographic appearance of primary sclerosing cholangitis?
Beading: segments of stricture alternating with dilated segments of intrahepatic and extrahepatic ducts.
With which bowel disease is PSC most often associated?
Ulcerative colitis.
Which cancer is the most feared complication of PSC?
Cholangiocarcinoma.
Why must IgG4-related sclerosing cholangitis be distinguished from PSC?
It looks similar but responds to corticosteroids and has IgG4-rich plasma cell infiltrates with storiform fibrosis.
Elsewhere in DurgiPedia
Connections
Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Sclerosing cholangitis: MedlinePlus Medical Encyclopedia (MedlinePlus, US National Library of Medicine, 2026).
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Representative model, for educational purposes only.