RESUMO
Objective To investigate the ultrasonic features and pathological basis of follicular variant of papillary thyroid carcinoma (FVPTC). Methods Ultrasonic presentation of 30 patients with FVPTC conifrmed by surgery and pathology from the Seventh People′s Hospital of Shaoxing during March 2002 and December 2012 were analyzed retrospectively and compared with pathological results. Results Ultrasonic presentation of 30 FVPTC cases could be classiifed into three types:(1) Six cases (20%, 6/30) of typeⅠ, with typical sonographic features of papillary thyroid carcinoma:nodules with irregular shape, unclear boundary, and very low echo inside, microcalciifcation could be seen. (2) Fourteen cases (47%,14/30) of typeⅡ, presented as clearer iso-echoic or hypo-echoic nodules, with irregular shape, angled and lobular edge, rare microcalciifcation. (3) Ten cases (33%, 10/30) of typeⅢ, presented as adenoma-like features, nodule with clear boundary and regular edge, uniform medium echo inside. The microscopic structure characteristics could be divided into three categories:6 cases of typeⅠ, lesions were featured with no obvious capsule, irregular shape and inifltrative growth;14 cases of type Ⅱ, lesions with irregular shape, which invading the capsule with partial protrusion and peripheral small satellite lesions;10 cases of typeⅢ, lesions with more complete envelope, more regular shape with no signiifcant or lower level and smaller extent invasion of the capsule. Differences in morphology, boundary, aspect ratio, internal echo, presentation of microcalciifcations between the encapsulated type (typeⅡ,Ⅲ) and non-encapsulated type (typeⅠ) FVPTC were statistically signiifcant (Fisher′s exact test, all P0.05). Conclusion Ultrasonic presentation of FVPTC show characteristics of both follicular tumor and papillary carcinoma, and the ultrasonic presentations are closely related to the pathological subtypes.