Granulomas in primary sclerosing cholangitis

Abstract: Granulomas in liver biopsy specimens from adult patients with chronic ductopenic cholestatic liver disease are a characteristic feature of primary biliary cirrhosis. However, we found a similar combination of abnormalities in 7 out of 100 native livers (7%) from patients who had orthotopic liver transplantation for primary sclerosing cholangitis. In a control group of native livers from 100 patients with primary biliary cirrhosis, the prevalence of granulomas was exactly the same, 7%. In the primary sclerosing cholangitis group, 13 additional livers showed a granulomatous epithelioid cell response, with or without foreign body type giant cells, to extravasated bile. All granulomas were noncaseating and non‐necrotizing; they consisted of epithelioid cells and often contained giant cells. Perigranulomatous lymphocytic infiltrates were generally mild to moderate. The granulomas involved portal tracts, scars, and hepatic parenchyma. Biopsy experience revealed that granulomas can be found in all stages of the disease. In contradistinction to the granulomas in primary biliary cirrhosis, the granulomas in primary sclerosing cholangitis did not represent granulomatous cholangitis – that is, they were not a feature of the duct destruction. The etiology of these lesions is not clear, but in some cases we found strong morphologic evidence that granulomas may form as a response to the leakage of bile or bile components. No evidence of infection or of sarcoidosis was found. Although adverse drug responses cannot be ruled out with certainty, review of the clinical histories made that mechanism unlikely. Thus, the presence of granulomas in chronic ductopenic cholestatic liver disease is not pathognomonic for primary biliary cirrhosis and, in rare instances (on average, in 3–4% of the biopsy samples), may be a feature of primary sclerosing cholangitis.