Extrapancreatic F-18 FDG accumulation in autoimmune pancreatitis.

We report two cases of autoimmune pancreatitis (AIP) in which fluorine-18 fluorodeoxyglucose (FDG) showed moderate accumulation in the pancreas, as well as in bilateral submandibular glands and in multifocal lymph nodes. FDG positron emission tomography (PET)/computed tomography (CT) is a useful diagnostic tool to assess the extrapancreatic lesions of AIP, which is a recently proposed new clinicopathological entity named immunoglobulin G4 (IgG4)-related systemic disease. Recognition of the FDG-PET/CT findings of IgG4-related sclerosing disease is crucial to avoid unnecessary surgery or other intervention because of similarities to malignant lymphoma or malignant tumor with multiple lymph node metastases.