Pancreatic cancer detected with 18F-FDG PET/CT in a case of IgG4-related disease.

We present a case of a 67-year-old male presenting with severe abdominal pain, laboratory tests revealed IgG levels of 63.5 g/L, IgG4 levels of 63.7 g/L, and negative results for ANCA (Anti-Neutrophil Cytoplasmic Antibodies), Hematuria immunofixation electrophoresis, as well as Cold globulin qualitative test. 18F-FDG PET/CT revealed multiple lesions with increased metabolism in the submaxillary saliva gland, intrahepatic bile ducts, prostate, seminal vesicle glands, and the body of the pancreas. Additionally, a circular cystic-solid lesion with metabolic heterogeneity was observed in the head of the pancreas, accompanied by visible dilatation of the pancreatic duct. The diagnostic imaging suggested IgG4-related disease (IgG4-RD), while pancreatic malignancy could not be definitively ruled out. The patient underwent fine-needle aspiration (FNA) biopsies of lung nodules and the prostate gland, all of which were consistent with the diagnosis of IgG4-RD. Additionally, FNA biopsy of a pancreatic lesion is consistent with the diagnosis of pancreatic ductal adenocarcinoma.