Castleman disease (CD) is a chronic lymphoproliferative disorder characterized by unexplained enlarged lymph nodes. According to lymph nodes distribution it contains two types of single-centric and multicentric (more than one site) disease. Multicentric Castleman disease (MCD) is rare, and shows unspecific manifestation with high misdiagnosis rate. Here we reported a case of MCD in a 43-year-old male. (18)F-FDG PET/CT imaging demonstrated higher FDG uptake in multiple lymph nodes and slightly FDG uptake in spleen and bone marrow. Right inguinal Lymph node biopsy was taken and the results confirmed CD.