ABSTRACT
<p><b>OBJECTIVE</b>To evaluate the ultrasound (US) features of the encapsulated papillary thyroid carcinoma (EPTC).</p><p><b>METHODS</b>Based on ultrasonographic features including shape, size, border, echogenicity, hypoechoic halo and microcalcification, 33 cases of EPTC were classified into two groups: 21 cases in irregular shape group and 12 cases in spherical or oval shape group.</p><p><b>RESULTS</b>EPTC in the irregular shape group showed some ultrasonographic features including jagged border, irregular tumor shape and marked hypoechogenicity, while the ultrasonographic features of EPTC in the spherical or oval shape group included smooth border, regular shape, isoechogenicity and hypoechoic halo. Hypoechoic halo and isoechogenicity were found more frequently in EPTC of spherical or oval shape group than those in EPTC of irregular shape group. The size of EPTC in the spherical or oval group was commonly larger than that of EPTC in the irregular shape group.</p><p><b>CONCLUSIONS</b>The findings indicate that EPTC have some ultrasonographic features similar to benign follicular thyroid tumors.</p>