A 68-year-old man underwent adjuvant radioiodine therapy for follicular variant papillary thyroid carcinoma. Post-therapeutic whole-body I-131 scan showed abnormal radioiodine uptake on the right side of back. SPECT/CT localized this abnormal activity from a small subcutaneous lesion with fat density between the right 10th and 11th rib. Under ultrasound-guided autopsy, the lesion was confirmed as lipoma.