FDG PET and PET/CT Monitoring of Autoimmune Pancreatitis Associated With Extrapancreatic Autoimmune Disease

We report a series of FDG PET findings of a 69-year-old male patient with autoimmune pancreatitis (AIP) associated with extrapancreatic disease. The first FDG PET revealed diffuse uptake of FDG in AIP and retroperitoneal fibrosis (RF). The second FDG PET after cessation of steroid treatment indicated subsiding of disease activity in AIP, continuous disease activity in RF, and new extrapancreatic lesions, including enlargement of a right salivary gland, nephritis, and lymphadenopathy. The last FDG PET under steroid treatment revealed reduced FDG uptake in the above abnormal FDG uptake lesions. A series of these FDG PET findings suggest the usefulness of FDG PET for the diagnosis and monitoring of AIP associated with extrapancreatic autoimmune diseases.