F-18 FDG PET/CT can help differentiate SAPHO syndrome from suspected metastatic bone disease.

A 20-year-old woman underwent magnetic resonance imaging of the spine for back pain, which demonstrated a solitary lesion in the T2 vertebral body suspicious for a metastasis. Subsequent computed tomography and bone scintigraphy identified several further sites of bony involvement but no primary malignancy. The patient was referred for F-18 FDG PET/CT which demonstrated intense FDG activity in the sternoclavicular and sacroiliac joints, in addition to the known thoracic vertebral body involvement suggesting spondyloarthropathy rather than malignant disease. During the course of investigations, the patient developed palmoplantar pustulosis leading to a diagnosis of SAPHO syndrome.