Calcified Thyroid Nodules: Review of the Significance of Peripheral Calcifications

ABSTRACT

Thyroid calcification may occur in both benign and malignant thyroid disease, but previous literature reports have indicated that calcification is more common in malignant lesions than it is in benign ones. Various patterns of calcification are seen, including microcalcification, coarse dense macrocalcification, and peripheral calcification. Microcalcification and coarse dense macrocalcification are two of the most specific features of thyroid malignancy. However, to date, the clinical significance of peripheral calcification remains unclear and therefore controversial. In this pictorial review, we describe the ultrasonographic features of calcified thyroid nodules and seek to delineate the spectrum and determine the clinical significance of peripheral calcification by correlating it with pathologic results. A broad spectrum of benign to malignant tumors is associated with peripheral calcification. Peripheral calcification in a thyroid nodule should be considered to indicate an indeterminate lesion, and ultrasonography-guided FNAB or core biopsy should be performed in order to exclude malignancy.