18F-FDG and 18F-NaF PET/CT Findings of a Multiple Myeloma Patient With Thyroid Cartilage Involvement.

Thyroid cartilage is a very rare extramedullary involvement location in multiple myeloma. We present both F-NaF and F-FDG PET/CT findings of a multiple myeloma patient with thyroid cartilage involvement. In this patient, increased FDG and more intensely increased NaF uptake were seen on thyroid cartilage. In addition, some bone lesions had more intense NaF than FDG uptake, and some were only NaF avid. Although F-FDG PET/CT has an important role in plasma cell neoplasms, we considered that F-NaF PET/CT is also very useful to detect small lytic lesions that might be overlooked on F-FDG PET/CT.