Sonographic Features of Thyroid Follicular Carcinoma in Comparison With Thyroid Follicular Adenoma

OBJECTIVES: The purpose of this study was to determine the sonographic features of thyroid follicular carcinoma in comparison with thyroid follicular adenoma. METHODS: This retrospective study included 36 pathologically proven follicular carcinomas (5 widely invasive and 31 minimally invasive) and 52 follicular adenomas in 88 patients who underwent thyroid surgery. We analyzed the sonographic features of each tumor, including maximum diameter, peripheral halo, echogenicity, echo texture, calcifications, and nodularity. The frequencies of the sonographic features were compared by χ(2) and Fisher exact tests between follicular adenomas and carcinomas. The relative risk of malignancy was evaluated by logistic regression analysis. RESULTS: Predominantly solid contents, hypoechoic echogenicity, a heterogeneous echo texture, the presence of calcifications, and an absent or irregular thick halo were associated with follicular carcinoma (P < .05). Logistic regression analysis demonstrated that predominantly solid contents, a heterogeneous echo texture, and the presence of calcifications were associated with significant increases in the relative risk of follicular carcinoma (odds ratios, 9.4, 24.9, and 25.6, respectively; P < .01). CONCLUSIONS: Sonography could provide useful information for differentiating follicular carcinoma from follicular adenoma.