FDG PET/CT in the detection of metastases in a patient with Tg and 131I WBS negative follicular thyroid cancer.

After a total or near total thyroidectomy and radioiodine ablation therapy for differential thyroid cancer (DTC), routine follow-up methods are (131)I or (131)I whole-body scanning (WBS) as well as serum thyroglobulin (Tg) and anti-thyroglobulin (anti-Tg) levels. We describe a case of a 41-year-old woman with follicular thyroid cancer. Although serum Tg level and (131)I WBS were negative after radioiodine ablation therapy, she had pain around her left medial clavicle. FDG PET/CT was performed for any undetected metastases. FDG PET/CT showed hypermetabolic bone metastases in the left medial clavicle. Biopsy confirmed metastases of the thyroid follicular carcinoma.