False-Positive Uptake of Radioiodine in Renal Hamartoma in a Patient With Differentiated Thyroid Cancer.

A 46-year-old woman with a history of papillary thyroid cancer status post total thyroidectomy underwent the second I radioiodine ablation therapy for lung metastases. Posttherapeutic whole-body I planar images showed diffuse uptake in the lungs and intense focal activity in both sides of the upper abdomen. SPECT/CT of the abdomen localized the uptake in the upper pole of the left kidney and the lower pole of the right kidney. The patient received bilateral partial nephrectomy with pathology demonstrating that these 2 renal lesions were renal hamartomas.