Ultrasonographic Characteristics of Subacute Granulomatous Thyroiditis

Objective: We wanted to describe the characteristic ultrasonography (US) features and clinical findings for making the diagnosis of subacute granulomatous thyroiditis. Materials and Methods: A total of 31 lesions from 27 patients were confirmed as subacute granulomatous thyroiditis by US-guided fine needle aspiration biopsy. We analyzed the ultrasonographic findings such as the lesion's size, margin and shape, the discrepancy between length and breadth and the vascularity. The clinical findings such as acute neck pain or fever were reviewed. The follow-up clinical and ultrasonographic data were reviewed for 15 patients. Results: The thyroid gland was found to be enlarged in five patients, it was normal size in 20 patients and it was smaller in two patients. All the lesions had focally ill-defined hypoechogenicity. Hypervascularity was not noted in any of the lesions. Painful neck swelling was present in 18 patients. An accompanying fever was documented in nine of the 18 patients. Twelve patients showed disappearance (n=3) or a decreased size (n=9) of their lesions on follow-up US. Conclusion: The presence of ill-defined hypoechoic thyroid lesions without a discrete round or oval shape is characteristic for subacute granulomatous thyroiditis, and particularly when this is associated with painful neck swelling and/or fever.