Sonographic Findings of Hashimoto's Thyroiditis and Associated Nodular Lesions

ABSTRACT

PURPOSE: To evaluate the sonographic findings of Hashimoto's thyroiditis and associated nodular lesions. MATERIALS and METHODS: We retrospectively reviewed the sonographic findings of twenty patients who had surgically confirmed Hashimoto's thyroiditis between 1 March 2005, and 26 November 2005. In these patients, we reviewed the sonographic findings of the associated focal nodular lesion. Assessed were size, homogeneity, and echogenicity of the diseased thyroid gland and shape, echogenicity, margin, rim, microcal cification of the associated nodules. Without knowledge of the pathological diagnosis of the nodular lesions, based on the sonographic criteria, the nodules were classified as either malignant or benign. RESULTS: Hashimoto's thyroiditis demonstrates a variety of sonographic findings for size, homogeneity, and echogenicity. Among the nineteen nodules that were sonographically diagnosed and pathologically confirmed, nine papillary cancers, seven nodular hyperplasias, two Huthle cell adenomas, and one focal hyalinized fibrosing nodule were included. All of the nine papillary cancers showed more than one malignant finding such as marked hypoechogenicity, an irregular shape, a taller than wide shape, a spiculated margin, or microcalcifications that were classified as malignant nodulea, and all of the ten benign nodules showed no malignant findings. Circumscribed isoechoic, hyperechoic, or hypoechoic nodules without calcification were classified as bending nodules. CONCLUSION: Hashimoto's thyroiditis demonstrates various findings on a sonographic examination,and associated various benign and malignant lesions. Moreover, a sonographic examination is helpful to differentiate between malignant and benign lesions in Hashimoto's thyroiditis as in the normal thyroid.