Hürthle cell thyroid adenoma with an eggshell calcification: sonographic-pathologic correlation.

We report the sonographic pathologic correlation in a case of Hürthle cell thyroid adenoma with an eggshell calcification in a 58-year-old woman. The mass was hypoechoic with a continuous eggshell calcification on gray-scale sonographic and intranodular vascularity power Doppler imaging. At pathological examination, the dystrophic calcification of eggshell type was located between the intact fibrous capsule and the main tumor matrix. Hürthle cell adenoma should be included in the differential diagnosis of a thyroid nodule with an eggshell calcification.