Abstract: Objective To analyze the clinicopathological characteristics in the patients with papillary thyroid carcinoma (PTC) and Hashimoto′s thyroiditis(HT). Methods A total of 1 416 patients with single lobe of PTC who underwent total thyroidectomy in Department of Surgery Ruijin Hospital were included in this study from January 2014 to December 2016. According to the preoperative concentration of thyroid globulin antibody and thyroid peroxidase antibody in serum, the patients were divided into group of PTC with HT (group A) and group of PTC without HT (group B). Based on the postoperative pathological examination, the patients were evaluated bilateral thyroid cancer involvement, tumor size, invasion of thyroid capsule, multifocality and central lymph node metastasis. Results There were 31.78% (450/1 416) patients with PTC and HT. The patients with contralateral PTC in group A was 53.78% and 42.34% in group B with statistical difference (P<; 0.001). Multifocality was 28.22% in group A and 22.77% in group B (P=0.027). Microcarcinoma (diameter<; 1 cm) was 51.11% in group A higher than that in group B (44.51%) significantly (P=0.020). However, invasion of thyroid capsule was lower in group A than that in group B (6.89% vs 10.77%) (P=0.021). There was no significant difference in central lymph node metastasis between two groups. Conclusions In patients with PTC and HT, tumor might be more likely bilaterally involved and multifocal and total thyroidectomy should be recommended to avoid residual cancer due to insufficient surgical resection.

Key words: Papillary thyroid carcinoma, Hashimoto's thyroiditis, Total thyroidectomy