CT and MRI features

Autoimmune pancreatitis (AIP) is a recently defined clinical entity. It is an uncommon disease with unique clinical and histological manifestations. It can be classified under the umbrella term of chronic pancreatitis and was first reported with the name of lymphoplasmacytic sclerosing pancreatitis with cholangitis in 1991. The term autoimmune pancreatitis was introduced in 1995. The clinical signs and symptoms mimic multiple diseases and early diagnosis is often difficult. The main pathologic abnormality is the infiltration of the pancreatic periductal areas with lymphocytes and plasma cells with subsequent destruction of the duct epithelium and venulitis [1]. Imaging plays a fundamental role in the diagnosis with some unique features that can be used to avoid a delayed diagnosis. Cross-sectional imaging can provide key findings to aid in the diagnosis and help avoid unnecessary testing and even surgery. In this chapter, we present the imaging findings associated with the pancreatic manifestations seen in patients with IgG4-related disease (IgG4-RD).