Lipoma: An Unusual Iodine-131 Uptake on Whole-Body Scanning: A Case Report

Whole-body radioiodine scintigraphy plays a major role in detecting metastases or recurrence of differentiated thyroid cancers. However, radioactive iodine uptake is not specific to thyroid tissue, and many physiological and pathological variants can bind radioactive iodine, resulting in false positives that can compromise the correct interpretation of results. We report the case of a 73-year-old patient with papillary thyroid carcinoma who underwent surgery 2 years ago, and whose whole-body scan, performed in the face of rising thyroglobulin levels, revealed abnormal fixation on the thigh, and further investigations suggested a lipoma. Our aim in reporting this case is to contribute to the knowledge of new false positives linked to iodine-131 fixation, in order to avoid unusual diagnostic errors that can lead to the unnecessary administration of therapeutic doses of iodine-131 or to aberrant surgical interventions.