IgG4-Related Disease Simulating Carcinoma Colon With Diffuse Peritoneal Carcinomatosis on 18F-FDG PET/CT

Abstract

IgG4-related disease (IgG4-RD) continues to be a diagnostic challenge and a great mimicker of malignancies. We report here a case of young man who presented with subacute intestinal obstruction with initial imaging and clinical features suggestive of carcinoma colon. F-FDG PET/CT showed diffuse peritoneal carcinomatosis pattern typically seen with abdominal malignancies. However, the histopathology and the raised IgG4 levels diagnosed it to be IgG4-RD. Although F-FDG PET/CT has typical patterns corresponding to the multisystemic involvement of IgG4-RD, the index case did not show any such findings.