Hashimoto Thyroiditis and Thyroid Ultrasound: A Prospective Study

Abstract

Purpose We performed a prospective study in patients with positive thyroid peroxidase antibodies (TPOAb), to describe their ultrasound (US) patterns and the prevalence of thyroid nodules. Methods In 195 consecutive patients, with positive TPOAb, thyroid US was performed by the same physician and equipment and categorized into four echographic patterns (EP). We determined the prevalence of thyroid nodules and their etiology confirmed by cytology or histology. Results The median TPOAb was 526 IUI/ml. EP1 or normal US was present in 9,7%; EP2 or early/indeterminate stage in 29,4%; EP3 or established thyroiditis in 45,4% and EP4 or advanced/late stage in 15,5% of the patients. TPOAb (median = 857 UI / ml) (p = 0.001), TSH and thyroid volume ​​were higher in EP3. A higher degree of fibrosis was associated with TPOAb > 1000 IU/ml(p = 0,003). Thyroid nodules were reported on US at 47,2% of HT. Fine needle aspiration(FNA) was performed in 49/60 nodules. Cytology: BII: 41 patients (83,7%), B V: 1 patient (2%): suspicious for lymphoma; B VI: 3 patients(6,1%) : Papillary thyroid carcinoma. Benign cytology was present in 56% of EP3 (p = 0,048). Conclusions Higher TPOAb, TSH levels, and thyroid volume were associated with EP3. Fibrosis correlated with TPOAb > 1000 IU/ml. In our population, benign nodules were associated with established thyroiditis patterns. The increased inflammation and immunological activity of Hashimoto thyroiditis (HT) could be a favorable environment for growth factors for benign nodular development.