Clinical and Pathological Characteristics of Patients With Papillary Thyroid Carcinoma Coexisting With Hashimoto’s Thyroiditis: A Retrospective Cohort Study

BACKGROUND: Papillary thyroid carcinoma (PTC) is the most common subtype of thyroid carcinoma, and Hashimoto’s thyroiditis (HT) has been postulated to have a relationship with PTC. This study aims to assess clinical and pathological characteristics of patients with papillary thyroid carcinoma coexisting with Hashimoto’s thyroiditis. METHODS: A retrospective study was conducted in a cohort of patients with thyroid carcinoma at the Department of Surgery, Shanghai General Hospital from January 2017 to December 2018. Medical records of patients who had PTC with or without HT were reviewed and clinical and histopathological characteristics of these patients were analyzed. RESULTS: A total of 632 patients with thyroid carcinoma were identified. Among them, 614 (97.15%) had PTC and 120/614 (19.0%) harbored PTC together with HT. PTC was significantly associated with HT, as compared with other histological subtypes (P < .001). Patients with coexisting PTC and HT (PTC + HT group) were significantly younger than patients with PTC alone (PTC group) (P = .008). There were more women in the PTC + HT group than in the PTC group (88.3% vs. 73.1%, P < .001). TSH, TGAb, and TPOAb levels were significantly higher in the PTC + HT group than in the PTC group (P ≤ .001). In addition, tumor diameter was smaller in the PTC + HT group than in the PTC group (P = .034). The PTC + HT group showed a significant better recurrence-free survival than the PTC group. Furthermore, immunohistochemical analysis revealed that patients in the PTC + HT group had a higher positive rate and higher expression intensity of Ki67 than patients in the PTC group. CONCLUSIONS: Our study revealed that patients with coexisting PTC and HT were younger, had smaller tumor diameters, a better prognosis, and higher positive rates and expression intensity of Ki67, than did patients with PTC alone.