False-Positive I-131 Uptake in a Benign Bone Lesion on Post-therapy Scan

WOS: 000366819800014PubMed ID: 26252335A 56-year-old woman underwent near-total thyroidectomy and papillary thyroid carcinoma without extrathyroidal extension was diagnosed. The serum thyroglobulin (Tg) level was 2.4 g/L, and anti-Tg was negative when serum thyroid-stimulating hormone level was 85 IU/mL. She received 100 mCi (3.7 GBq) of I-131. Besides the residual thyroid tissue, a focal uptake in the left clavicular bone was seen on posttherapy I-131 images. Then, CT and MRI were performed to diagnosis. All imaging findings suggested that it was a benign bone cyst. At 6-month follow-up, the serum Tg level was undetectable with the thyroid-stimulating hormone level of more than 150 IU/mL