18F NaF brain metastasis uptake in a patient with melanoma.

A 57-year-old man with a history of metastatic melanoma and sclerotic bone lesions seen on CT was referred for F NaF PET/CT evaluation of active skeletal metastases. While the bone lesions had no uptake and were therefore thought to represent sequela of previously treated disease, an unexpected area of F NaF uptake was identified in the left temporal lobe. Concurrent contrast-enhanced brain MRI re-demonstrated a large metastasis, also seen on previous MRI scans done at another institution.