Ultrasound findings suggestive of microscopic extranodal extension in papillary thyroid carcinoma.

Abstract

Purpose: Extranodal extension (ENE) of metastatic carcinoma in patients with papillary thyroid carcinoma (PTC) has been associated with an increased risk of recurrent disease, persistent disease, and disease-specific mortality; however, ultrasound findings suggestive of ENE have not been well established. In this study, we aimed to identify ultrasound findings suggestive of microscopic ENE and validate them histologically.

Methods: We retrospectively examined the ultrasound and histological findings of 21 PTC patients with microscopic ENE and 46 without ENE.

Results: Node matting, irregular shapes, ill-defined jagged border, and perinodal hyperechoic rims were observed in 40.0%, 57.1%, 42.9%, and 57.1% of lymph nodes with ENE, respectively, and the frequencies were significantly higher than those without ENE, with p values less than 0.05, 0.0005, 0.0001, and 0.0001, respectively. The sensitivity and specificity of cases with any one of irregular shapes, ill-defined jagged border, and perinodal hyperechoic rims were 81.0% and 82.6%, respectively. Histologically, node matting, irregular shape, ill-defined jagged border, and a perinodal hyperechoic rim correspond to adhesion between lymph nodes, extensive invasion, minimal invasion, and invasion into adipose tissue, respectively.

Conclusions: We would argue that any irregular shape, ill-defined jagged border, and perinodal hyperechoic rim can be accepted as findings indicative of microscopic ENE.