PURPOSE Papillary thyroid carcinoma (PTC) is frequently associated with diffuse lymphocytic thyoiditis (LT) at histology and serum autoantibodies to thyroglobulin (TgAb) and to thyroperoxidase (TPOAb). The influence of LT and thyroid autoantibodies on the prognosis of PTC is debated. We evaluated the clinical course of a large group of PTC patients according to the presence or absence of LT (LT+ and LT-) and thyroid autoantibodies. METHODS We evaluated 194 consecutive and non-selected PTC patients treated with total thyroidectomy plus ¹³¹I ablation between 2007 and 2009, followed for 7.2 years (mean). 72 patients had follicular variant of PTC, 97 classic, 16 tall cells and the remaining 9 others variants (solid or oxyphilic cells). LT was diagnosed in presence of >10 lymphocytes/field (40x). At the time of ablation, all patients underwent measurement of Tg, TgAb and TPOAb, neck ultrasound and whole body scan. After ablation, patients underwent Tg (Beckman Coulter), TgAb and TPOAb (Tosoh) measurement and neck ultrasound (associated with other imaging if required) every 6-12 months. PTC was considered in remission according to the following criteria: un-stimulated Tg
