We report the case of a 59-year-old woman with a history of follicular thyroid cancer who had reoperation for suspected local tumor recurrence as laboratory (tumor marker), imaging findings (ultrasound, I-131 scintigraphy and Tc-99m-MIBI scintigraphy), and also fine needle aspiration (FNA) cytology were equivocal. However, postoperative histopathology revealed a parathyroid adenoma.