Follicular Thyroid Carcinoma With an Eggshell Calcification

Objective. The purpose of this series is to report 3 cases of follicular thyroid carcinoma with an eggshell calcification along with their imaging findings. Methods. Imaging findings on gray scale and power Doppler (PD) sonography (n = 3), computed tomography (CT; n = 3), and integrated fluorodeoxyglucose F 18 ( 18 F‐FDG) whole‐body positron emission tomography (PET)/CT (n = 1) were assessed. Results. Of the 3 cases, two 75‐year‐old women had bone metastasis, and one 54‐year‐old woman had a thyroid incidentaloma on sonography. All 3 cases had a spherical mass with an interrupted eggshell calcification on gray scale sonography and CT; 2 revealed intranodular vascularity on PD sonography, and 1 showed intense hypermetabolism (maximum standardized uptake value, 7.9 g/mL) on integrated 18 F‐FDG whole‐body PET/CT. Conclusions. Follicular carcinoma should be considered in the differential diagnosis of a thyroid nodule with an eggshell calcification.