Sonographic findings of metastatic disease to the thyroid

The goal of this study was to evaluate the sonographic findings of thyroid metastases arising from non-thyroid primaries. The study over a 5-year period comprised nine patients who had histopathologically proven metastatic disease to the thyroid. Ultrasonography was available in all cases. Ultrasound-guided needle aspiration was performed on 10 suspected nodules as determined by ultrasound. The Ultrasonographic findings were analyzed in two different ways. The first analysis included only those nodules biopsed, and the second analysis included all the nodules, biopsed and non-biopsed. The primary neoplasms were breast carcinoma (n=6), uterine leiomyosarcoma (n=1), cervical carcinoma (n=1), and nasopharyngeal carcinoma (n=1). Excluding 2 nodules, the 8 remaining metastatic nodules exhibited ill-defined hypoechoic character with heterogeneous texture. The other two nodules showed relatively circumscribed iso- or hypo-echoic character with cystic portion. From the analysis of ultrasonographic findings including all thyroid nodules irrespective of pathologic proof, 7 cases - excluding the 2 cases from the 9 cases - showed unilateral or bilateral multiple nodules suspected of metastasis. There was no evidence of microcalcification in any thyroid nodules. In conclusion, the sonographic findings of the thyroid metastatic nodules were not specific, but unilateral or bilateral multiple suspected thyroid nodules without evidence of microcalcification may be suggestive of metastatic nodules among patients with a known primary non-thyroidal tumor.