Delusory Radioiodine Uptake in Endometriotic Ovarian Cyst

A 25-year-old woman with a known case of papillary thyroid carcinoma conventional type referred to our center for treatment with radioactive iodine after total thyroidectomy. She received 200 mCi of radioiodine, and in the whole-body scan 1 week after the radioiodine therapy, an area of increased absorption was seen on the right side of the pelvis, which was diagnosed as an endometriotic ovarian cyst in the follow-up examinations.