Sonographic Features Of Enlarged Central Compartment Lymph Nodes In Thyroid Microcarcinoma And Its Clinicopatholologic Features

Objective:1.To evaluate the ultrasonographic features of enlarged central lymph nodes in thyroid microcarcinoma.2.To detect the subgroups(paratracheal,pretracheal and prelaryngeal lymph nodes)of central lymph nodes by ultrasonography.3.To dissect the interrelated factors of central lymph node metastasis in thyroid microcarcinoma.Methods:The data of 422 cases of thyroid microcarcinoma in Shanxi Medical Universitiy Affiliated Tumor Hospital from January 2013 to December 2015 was investigated retrospectively.For the enlarged central lymph nodes,the results of ultrasonography,intraoperative detection and surgical pathology were compared,and the features of enlarged lymph nodes by ultrasonography were evaluated.Univariate and multivariate analyses were performed to analyze the sonographic features and related factors of central lymph node metastasis in thyroid microcarcinoma.Results:In 422 cases of thyroid microcarcinoma,128 cases of central compartment lymphadenopathy were identified,including 276 nodes detected by preoperative ultrasound.The ultrasonic characteristics of central lymph nodes included hypo-echoic(98.6%,272/276),L/T? 2(63.8%,176/276),absence of echogenic hilus(72.1%,199/276),poor blood supply(91.7%,253/276).Surgery detected 978 paratracheal lymph nodes,and 522 nodules were? 5.0 mm in diameter(53.4%).Among 422 patients,100 cases with paratracheal lymph nodes were confirmed by pathology(23.7%).Preoperative ultrasound undetected pretracheal and prelaryngeal lymph nodes,and surgery detected 51 nodes,including 30 nodules ? 5.0 mm in diameter(58.8%)and 5 nodules> 10.0 mm in diameter(9.8%),of whom 7 cases with pretracheal and prelaryngeal lymph nodes were identified by pathology.Among 422 patients,103 cases with central lymph nodes metastasis were confirmed by pathology(24.4%).Univariate analysis revealed that age< 45 years(P =0.000),tumor size> 5 mm(P=0.001),lateral neck lymph node metastasis(P =0.000),multifocality(P =0.001),microcalcification(P =0.024)were statistically significant(all P< 0.05).Gender(P=0.410),tumor situation(P =0.083),chronic lymphocytic thyroiditis(P =0.839),extrathyroidal extension(P =0.144),echogenicity(P =0.443),margin(P =0.586),taller-than-wide shape(P =0.345),blood supply(P =0.999)were not significantly related to the presence of central compartment lymph node metastasis(all P> 0.05).Multivariate analysis revealed lateral neck lymph node metastasis(P =0.000),multifocality(P =0.001),microcalcification(P =0.000)were independent risk factors(all P<0.05).Conclusion:1.The ultrasonic characteristics in central lymph node included hypo-echoic,L/T?2,lack of echogenic hilus,poor blood supply.2.Preoperative ultrasound was prone to undetected,which may be involved with the deep location,the smaller diameter and complicated anatomy.The present findings emphasize that a negative US does not obviate the need for careful exploration of the central compartment to minimize the risk of persistent or recurrent local disease.3.Central lymph node metastasis was significantly associated with lateral neck lymph node metastasis,multifocality,microcalcification.When these characteristics are detected on preoperative US,the sonographer should scan carefully.