Ectopic Thyroid Tissue in the Uterus Identified by Iodine-131 SPECT/CT

A 45-year-old woman underwent a total thyroidectomy and was subsequently treated with 1110 MBq of radioactive iodine-131 ablation therapy for papillary thyroid cancer. A post-therapy iodine-131 whole-body scan revealed a focal uptake in the mid-pelvic area. To identify the exact anatomical location, SPECT/CT images were taken. The SPECT/CT fusion images revealed that the uptake was in the uterus, which was considered as radioactive iodine-avid ectopic thyroid tissue in the uterus.