Spurious metastasis on whole body scans in a patient with thyroid carcinoma

A young woman received 65 mCi I-131 for ablation of recurrent functioning thyroid tissue in the thyroid bed after prior ablation. Following this dose, I-131 remained localized bilaterally in submandibular salivary tissue for more than 18 days. There was no evidence of metastatic disease in the salivary glands. The persistent I-131 retention, another cause of "spurious metastasis", may have occurred red because of protein binding of iodide carried out by salivary peroxidase. (J. Endocrinol. Invest. 21: 541-543, 1998) (C) 1998, Editrice Kurtis.