Autoimmune hepatitis/primary biliary cirrhosis overlap syndrome and associated extrahepatic autoimmune diseases.

To assess the prevalence of concurrent extrahepatic autoimmune diseases in patients with autoimmune hepatitis (AIH)/primary biliary cirrhosis (PBC) overlap syndrome and applicability of the 'mosaic of autoimmunity' in these patients.The medical data of 71 AIH/PBC overlap patients were evaluated for associated autoimmune diseases.In the study population, 31 (43.6\%) patients had extrahepatic autoimmune diseases, including autoimmune thyroid diseases (13 patients, 18.3\%), Sjögren syndrome (six patients, 8.4\%), celiac disease (three patients, 4.2\%), psoriasis (three patients, 4.2\%), rheumatoid arthritis (three patients, 4.2\%), vitiligo (two patients, 2.8\%), and systemic lupus erythematosus (two patients, 2.8\%). Autoimmune hemolytic anemia, antiphospholipid syndrome, multiple sclerosis, membranous glomerulonephritis, sarcoidosis, systemic sclerosis, and temporal arteritis were identified in one patient each (1.4\%). A total of 181 autoimmune disease diagnoses were found in our patients. Among them, 40 patients (56.4\%) had two, 23 (32.3\%) had three, and eight (11.3\%) had four diagnosed autoimmune diseases.A large number of autoimmune diseases were associated with AIH/PBC overlap patients. Therefore, extended screening for existing autoimmune diseases during the routine assessment of these patients is recommended. Our study suggests that the concept of 'mosaic of autoimmunity' is a valid clinical entity that is applicable to patients with AIH/PBC overlap syndrome.