Gray-scale and color Doppler sonographic findings in a case of subacute granulomatous thyroiditis mimicking thyroid carcinoma

Subacute granulomatous thyroiditis is a common disease of unknown cause and is usually self-limiting, with complete resolution of symptoms occurring spontaneously or after steroidal treatment. We report a case of subacute granulomatous thyroiditis in a 62-year-old woman whose clinical presentation was consistent with thyroid carcinoma. Gray-scale and color Doppler sonography revealed marked enlargement of the left lobe of the thyroid and markedly hypoechoic, ill-defined focal areas in both lobes. No flow was noted on color Doppler sonographic examination. Fine-needle aspiration of the thyroid was performed, and histopathologic examination of the specimen confirmed the diagnosis of subacute granulomatous thyroiditis. The patient received prednisolone therapy (20 mg/day) for 2 weeks and recovered well. This case report is the first to describe the gray-scale and color Doppler sonographic appearances of subacute granulomatous thyroiditis. This disease should be included in the differential diagnosis of patients with clinical signs and symptoms of thyroid carcinoma. Histopathologic examination is necessary to confirm the diagnosis.