A CASE OF RADIATION THYROIDITIS DIAGNOSED BY ULTRASONOGRAPHY

We describe a patient with radiation thyroiditis diagnosed by ultrasonography. The patient was a 56-year-old male who had a history of receiving irradiation therapy to the neck for a malignant lymphoma 27 years before. After the irradiation therapy, he was followed up by his physician, and was referred to the hospital with suspected recurrent disease owing to the appearance of an induration of the neck. Based on physical examination, ultrasonography, computed tomography and fine-needle aspiration biopsy of the induration, it was found keloid. Although the thyroid gland was not palpable, ultrasonography which was examining the keloid-like induration accidentally visualized the thyroid region and offered a suspicion of radiation thyroiditis. Serum levels of thyroid hormone showed severe hypothyroidism. The result of fine-needle aspiration biopsy of the thyroid also suggested radiation thyroiditis. From these findings the patient was diagnosed as radiation thyroiditis associated with severe hypothyroidism. Characteristic ultrasonographic findings may contribute to make a diagnosis of thyroid disease, especially when the thyroid gland is not palpated.