Clinical presentation, diagnosis and management of autoimmune pancreatitis.

Autoimmune pancreatitis (AIP) is a relatively rare but clinically important form of chronic pancreatitis that has typical clinical, serologic, histologic, and radiologic findings. Patients frequently present with jaundice and cholestatic serum liver function tests. The serum IgG4 level is typically elevated with a lymphoplasmacytic infiltrate in affected tissue that stains by immunohistochemistry for IgG4-containing cells. Characteristic radiologic features include pancreatomegally and pancreatobiliary duct strictures. Extrapancreatic manifestations are increasingly being recognized. AIP typically rapidly responds to corticosteroid therapy and possibly other immunosuppressive medications. A missed diagnosis can result in unnecessary pancreatic surgery with unnecessary morbidity and mortality. Although significant progress in disease pathophysiology has occurred during the past decade, there is still much to learn regarding disease pathogenesis and management. With further research, the diagnostic algorithm, treatment strategy, follow-up protocol, and long-term prognosis should become better defined.