Differentiated thyroid cancer (DTC) patients with negative serum thyroglobulin (Tg), negative 131I whole–body scintigraphy (131I-WBS) at first post-ablation and progressively increased TgAb level are a relatively rare entity in the follow-up after total thyroidectomy and radioactive iodine therapy. This evidence concerns the gene TG and differentiated thyroid carcinoma.