Table 5.

Summary of findings reported in the 11 papers included in the systematic review but not in the meta‐analyses

Ref	First author	Main findings
[20]	Zhu	Tumour size >40 mm, capsular invasion, metastatic cervical lymph nodes positively correlated with the risk of postoperative recurrence of MTC.
[28]	Guo	In presence of cystic change, circumscribed margin, regular shape, no calcification, no rich vascularity, and normal cervical lymph nodes, MTC is easily misdiagnosed as benign by US.
[30]	Wang	The higher frequency US presentation of MTC was the low‐echo tumour in round or quasi‐circular shape, with obscure boundary and often combined with rough calcification.
[33]	Bao	The common US findings for MTC were solid composition, hypoechogenicity, regular sharp, well‐defined margin, and calcifications.
[34]	Zhou	Sonographic features of MTC are similar to those of small papillary carcinomas but greatly different from those of large papillary ones.
[36]	Sesti	US can detect recurrent MTCs with an accuracy positively correlated with calcitonin levels.
[37]	Choi	The predominant US findings of MTC included solid internal content, round‐to‐oval shape, smooth margins, hypoechogenicity, and micro‐ or macro‐calcifications.
[38]	Lee	MTCs differ from PTCs in size, presence of a cystic change, and echotexture.
[39]	Cai	The typical sonographic features of MTC are hypoechogenicity, predominantly solid, irregularly shaped with intranodular micro‐ or macro‐calcifications.
[40]	Kim	US findings for MTC are not greatly different from PTC except for the prevalence of an ovoid‐to‐round shape.
[43]	Saller	Conventional US reveals a combination of hypoechogenicity, intranodular calcifications, and absence of ‘halo sign’ in the vast majority of MTC.

Abbreviations: MTC, medullary thyroid carcinoma; PTC, papillary thyroid carcinoma; US, ultrasound.