Clinical Profile of Autoimmune Pancreatitis and Its Histological Subtypes

The objective of this study was to clarify the clinical and pathophysiological characteristics of autoimmune pancreatitis (AIP) and its subtypes (lymphoplasmacytic sclerosing pancreatitis [LPSP] and idiopathic duct-centric pancreatitis [IDCP]) seen around the world.An international multicenter survey of AIP was conducted in 15 institutes from 8 countries. We compared clinical and pathologic profiles of AIP (n = 731) and the clinical profiles of LPSP (n = 204) and IDCP (n = 64) patients.Patients with LPSP were approximately 16 years older than IDCP patients. Obstructive jaundice was a more frequent presentation in LPSP versus IDCP (75% vs 47%, P < 0.001), whereas abdominal pain (41% vs 68%, P < 0.001) and acute pancreatitis (5% vs 34%, P < 0.001) were more frequent in IDCP patients. Patients with LPSP were more likely to have diffuse swelling of the pancreas (40% vs 25%, P = 0.037) and elevated serum IgG4 levels (63% vs 23%, P < 0.001) but less likely to be associated with ulcerative colitis (1% vs 16%, P < 0.001). Clinical profiles of non-histologically confirmed AIP from Asia, the United States, and United Kingdom corresponded with that of LPSP, whereas those from Italy and Germany suggested a mixture of LPSP and IDCP.Autoimmune pancreatitis is seen all around the world, with regional differences in the pathologic and clinical features. Lymphoplasmacytic sclerosing pancreatitis and IDCP have distinct clinical profiles.