Unexpected Radioiodine Uptake in 131I Whole-Body Scan

A 23-year-old woman underwent a near-total thyroidectomy approximately 4 months prior due to papillary carcinoma. To eliminate residual thyroid tissue, she was administered 130 mCi of 131I during her initial radioiodine therapy session. After receiving therapy for 3 days, a focus of radioiodine uptake was noted in the left pelvic cavity on the posttherapy 131I whole-body image. Further analysis using SPECT/CT imaging pinpointed the uptake to the left ovary. Histopathological findings confirmed the presence of a mature teratoma in the ovary.