Abstract
Autoimmune pancreatitis (AIP) is a chronic inflammatory and fibrosing disease of the pancreas classified as Type 1 and Type 2 based on two distinct patterns of histopathologic and clinical presentation. First suspected in 1961 with a report of an autoimmune form of chronic pancreatitis, and first termed AIP in 1995, it was not until 2009 when an international panel of experts met at the Honolulu consensus conference on AIP that a classification of AIP and its subtypes was formally developed and later characterized in the International Consensus Diagnostic Criteria by the International Association of Pancreatology in 2010. Overall, AIP is an uncommon cause of acute or chronic pancreatitis, with an incidence of 3.1 per 100,000 persons per year reported in Japan, but with yet unclear worldwide incidence. Type 1 AIP is the more common of the two subtypes, which is also three times more prevalent in men and occurs in an older age-group around the 7th decade of life. The etiology of AIP is still under investigation; however, it appears that both genetic and environmental exposures play a role.