I-131 uptake demonstrated in the appendix on a posttreatment scan in a patient with thyroid cancer

Precise localization of focal radioiodine uptake in post-treatment whole body planar I-131 scans can sometimes be difficult because of lack of anatomic landmarks and in areas of physiological uptake. We report oil a 42-year-old male with well-differentiated papillary thyroid cancer, status post total thyroidectomy and a history of radioactive iodine ablation, who presented with rising thyroglobulin levels and was re-treated with 200 mCi of I-131. Five days later, the whole body planar I-131 scan showed focal iodine uptake in the right lower quadrant of the abdomen. SPECT/CT of the abdomen was performed, which localized this focal iodine uptake to a normal appearing appendix.