Ultrasound findings of subacute thyroiditis: a single institution retrospective review.

Background: High resolution ultrasonography features have also been described as having a useful supporting role in the diagnosis of subacute granulomatous thyroiditis (ST), and images are generally characterized by heterogeneous hypoechoic areas of the affected tissue with lack of flow on color Doppler US.

Purpose: To determine the sonographic features of subacute granulomatous thyroiditis.

Material And Methods: We reviewed the medical records of patients referred at the Endocrine and Metabolic Unit of our Institution between January 2010 and December 2011.

Results: A total of 7520 patients were evaluated in our department between January 2010 and December 2011. Among them, 22 (0.3%) patients had a diagnosis of ST (19 women and 3 men, 45.4 ± 9.7 year; range, 33-62 years). Ultrasound examination showed bilateral ST in 64% of patients. Thyroid volume was 13.2 ± 7.7 mL, without difference if ST was unilateral (13.2 ± 7.1 mL) or bilateral (13.9 ± 8.3 mL). On grayscale US, heterogeneous diffusely or focally marked hypoechoic areas, like "lava flow", were found in all the lesions.

Conclusion: Our data confirm the high sensitivity of US in the diagnosis of ST: diffuse hypoechoic and confluent areas with the characteristic features like "lava flow".