Prevalence of malignant tumors and adenomatous lesions detected by ultrasonographic screening in patients with autoimmune thyroid diseases.

Background: Thyroid ultrasonography (US) is the most sensitive method for detecting thyroid nodules, and US-guided aspiration biopsy is the most accurate diagnostic procedure for thyroid nodules. We performed this retrospective study to establish the prevalence of thyroid nodules in Graves' disease and patients with Hashimoto's thyroiditis at the time of their initial visit.

Methods: We performed thyroid US as routine screening in 1652 patients with Graves' disease and 2036 Hashimoto's thyroiditis and performed US-guided fine-needle aspiration biopsy when the diameter of a nodule >1 cm or a nodule was suspected of being malignant.