Steroid-Responsive Chronic Pancreatitides: Autoimmune Pancreatitis and Idiopathic Duct-Centric Chronic Pancreatitis

Abstract

Two different forms of steroid-responsive pancreatitides are recognized, with both being referred to as “autoimmune pancreatitis.” They differ significantly in their clinical, histological, and epidemiological features. It has recently been suggested that the term “AIP” be reserved for the disease associated with elevated serum and tissue IgG4, while the term idiopathic duct centric chronic pancreatitis (IDCP) be used for pancreas-specific form. Clinically the most frequent presentation is painless obstructive jaundice with a mass/enlargement of the pancreas at imaging, and the differential diagnosis with cancer is frequently difficult. AIP is part of a multiorgan disorder called IgG4-related disease and any organ may be involved. Therefore, more than 50 % of the patients suffering from AIP present an inflammatory involvement of other organs (particularly bile ducts, kidneys, and salivary glands). Serum IgG4 elevation is not pathognomonic of AIP and serum IgG4 should be used in combination with other features to make a diagnosis of AIP. Both AIP and IDCP respond to steroids. In relapses of AIP the use of immunosuppressive drugs or of biologic agents may be considered.