Bone metastasis detected by FDG PET in a patient with breast cancer and fibrous dysplasia

Bone scintigraphy is sensitive for detecting bone metastases in patients with malignancies. However, it is often difficult to differentiate bone metastases from other nonmalignant lesions. We encountered a patient with a history of breast cancer who showed substantial elevation of tumor markers 4 years after surgery. Although there were no subjective symptoms and the bone scan showed multiple hot spots, which were similar to previous scans and which had been diagnosed as fibrous dysplasia on radiographs, a whole-body FDG PET scan showed a solitary area of intense uptake at the site of one of the hot spots in the bone scan. A solitary bone metastasis was confirmed by MRI and the patient then received radiation therapy and the elevated tumor markers of CEA and CA 15-3 were normalized after the therapy.