The term 'overlap syndrome' has been used to describe the presence of both autoimmune hepatitis and primary biliary cholangitis or primary sclerosing cholangitis in the past. As this term is misleading, the term 'variant syndrome' should be used preferably. Laboratory features, serology, histology and bile duct imaging contribute to the diagnosis of 'variant syndromes'. Patients with a suspected variant syndrome should receive a complete work-up with liver histology, serology and - if not conclusive, bile duct imaging. Liver histology is usually reliable to recognize secondary autoimmune hepatitis in patients with primary cholestatic disease. An histological activitiy index of >4 usually is commonly seen in patients with variant syndrome. Identification of variant syndrome is very important, as appropriate - in most cases additional - immunosuppressive treatment is necessary and most patients will respond promptly.
