Imaging autoimmune pancreatitis.

Author(s): Irie, Nojiri, Kamochi

Computed tomography and MRI findings of 40 cases of autoimmune pancreatitis (AIP) were reviewed, and AIP classified into three types: diffuse, segmental and multifocal. A capsule-like rim can play an important role in diagnosing AIP. A smooth contour of the lesion without circumference fat tissue change is also considered to be a characteristic of AIP. The important differential diagnosis of diffuse type AIP is lymphoma. Differentiating clues are main pancreatic duct change and enhancement pattern on dynamic study. Differentiation between segmental type AIP and pancreatic cancer is often difficult or may be almost impossible. Although rare, AIP may show multifocal delayed enhanced masses within the pancreas. Recognition of this type of AIP is mandatory in diagnosing pancreatic abnormalities.