What distinguishes primary sclerosing cholangitis (PSC) from PBC?

Primary sclerosing cholangitis (PSC) is distinguished by its association with inflammatory bowel disease, particularly ulcerative colitis. PSC is a chronic condition characterized by progressive inflammation and destruction of the bile ducts, both intrahepatic and extrahepatic. Patients with PSC often have co-occurring ulcerative colitis, with studies showing that a significant percentage of PSC patients also have this form of inflammatory bowel disease.

In contrast, primary biliary cholangitis (PBC) does not have this association. PBC is primarily an autoimmune disorder affecting the small bile ducts within the liver and is characterized by the presence of anti-mitochondrial antibodies.

While gender predisposition may also differ among these diseases, with PBC being more common in women, the defining distinguishing feature between PSC and PBC is the relationship with ulcerative colitis. Destruction of extrahepatic ducts can occur in both conditions, so it is not specific to PSC. Therefore, the association with ulcerative colitis is a hallmark that helps differentiate PSC from PBC.