Apparently Benign 131I Adrenal Uptake

A 60-year-old man suffering from papillary thyroid cancer (pT2 pN0(0/21) cM0) underwent diagnostic 131I whole-body scintigraphy with recombinant thyroid-stimulating hormone for follow-up after thyroidectomy and adjuvant 131I therapy with 4.2 GBq. A focal uptake of radioiodine was found in the right adrenal gland, which had not been seen on the initial posttherapeutic images; therefore, an adrenal metastasis was suspected. However, the diagnostic workup including contrast-enhanced MRI as well as endocrine laboratory tests indicated a benign etiology showcasing a very rare case of false-positive radioiodine uptake in the adrenal gland. The imaging follow-up after 1 year showed no significant changes.