Autoimmune liver diseases comprise a spectrum of progredient idiopathic inflammatory diseases. Typical histological features of autoimmune hepatitis (AIH) include the pattern of chronic hepatitis with predominant plasma cell-rich interface activity, rosetting of hepatocytes, and emperipolesis. Florid bile duct lesions are the key feature of primary biliary cholangitis (PBC); onion-like periductal fibrosis characterizes the primary sclerosing cholangitis (PSC). Variants of AIH, or overlap syndromes, show intersecting histomorphologic findings with PBC or PSC. The diagnosis of the different autoimmune inflammatory liver diseases is based on clinical presentation, a hepatitic or cholestatic pattern of liver enzymes, immuno-serological findings, image analysis in PSC, and liver biopsy as a facultative or obligatory adjunct. Liver biopsy plays a major role in the diagnosis of AIH, small-duct PSC, AMA-negative PBC, IgG4-related diseases, overlap syndrome, and in the recognition of concurrent liver diseases, especially drug-induced liver diseases. Herewith pathologists can help clinicians find adequate therapy for different autoimmune inflammatory liver diseases.
Keywords: AIH; Autoimmune hepatitis; Histologic findings; IgG4-related diseases; Liver biopsy; Overlap syndrome; PBC; PSC; Primary biliary cholangitis; Primary sclerosing cholangitis.