Table 1.

Ultrasound images of thyroid metastasis from renal clear cell carcinoma reported in previous literatures.

Case number	First Authors (PubMed Unique Identifier, year)	Number of reported cases	Ultrasonographic features
1	Song OK et al[7] (27956733,2017)	9	Single lesion (33.3%), multiple lesions (66.7%), solid echo pattern (66.7%), clear boundary (88.9%), regular shape (33.3%), with calcification (22.2%), and with rich blood flow (100%)
2	Cilengir AH et al[8] (28096905,2016)	1	Single lesion, solid, hypoecho, with clear boundary, irregular shape, lobulated, with microcalcification, and with rich blood flow
3	Ramírez-Plaza CP et al[9] (25827295,2015)	1	Multiple lesion, solid-cystic, unclear boundary, irregular shape, without calcification, and with rich blood flow in the solid region
4	Gheorghiu ML et al[10] (31258806,2016)	1	Single lesion, solid-cystic, unclear boundary, regular shape, and with rich blood flow in the solid region
5	Wada N et al[11] (15912297,2005)	1	Multiple lesions, solid, hypoecho, clear boundary, irregular shape, with calcified plaque, and with poor blood flow