18F-FDG PET/CT for Diagnosis of Castleman Disease: A Case Report

A 73-year-old man was admitted to our hospital with fever of unknown origin (FUO). Laboratory findings showed high levels of C-reactive protein (25.99 mg/dL) and interleukin-6 (IL-6) (14.7 pg/mL). Computed tomography revealed right lateral pleural effusion and ascites. 18F-Fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT revealed intense tracer accumulation in the cervical and para-aortic nodal chains, and lymph node excisional biopsy showed mixed type Castleman disease. Prednisolone and IL-6 receptor antibody, tocilizumab, achieved dramatic results. FDG PET/CT is a valuable modality for assessment of etiology in patients with FUO. This can help identify suitable glands for excisional biopsy in such cases.