To evaluate the ultrasonographic features of enlarged central lymph nodes in thyroid microcarcinoma and its clinical significance.

The data of 422 cases of thyroid microcarcinoma in Shanxi Medical University Affiliated Tumor Hospital from January 2014 to December 2014 was investigated retrospectively. For the enlarged central lymph nodes, the results of ultrasonography, intraoperative detection and surgical pathology were compared, and the ultrasound characteristics of enlarged lymph nodes were assessed.

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.

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. The sonographer should be familiar with the status of central lymph node metastasis and ultrasonic features. The sonographer also should expand the area of the initiative while detect the central compartment lymphadenopathy, which is important guiding for surgical removal of thyroid cancer and lymph node metastasis.