Predicting the factors of lateral lymph node metastasis in papillary microcarcinoma of the thyroid in eastern China.

Introduction: Lateral lymph node metastasis is common in papillary thyroid microcarcinoma (PTMC). The present study evaluated the clinicopathologic characteristics and ultrasonographic (US) findings in predicting lateral LNM from PTMC in eastern China.

Materials And Methods: A total of 176 patients with confirmed PTMC by final histological examination who underwent central lymph node dissection (LND) and lateral LND were enrolled in our study. The clinicopathological and US data from the cases were analyzed retrospectively to determine the independent predictive factors for lateral LNM. Then, a scoring system was developed on the basis of independent factors. The sum of the points for individuals was evaluated for the value in predicting lateral LNM.

Results: Central LNM, underlying Hashimoto's thyroiditis, upper pole location, no well-defined margin and presence of calcifications were independent predictive factors for lateral LNM on multivariate analysis. Clinicopathological and US index points were statistically significant, with ≤ 2 favoring lateral LNM negativity with a sensitivity of 83.3 %, positive predictive value of 89.6 % and negative predictive value of 72.9 %.

Conclusions: When the evaluation for lateral lymph nodes from a preoperative approach is inadequate or not obvious, our scoring system for prediction of lateral LNM can be another choice. Patients with clinicopathological and US index points ≤ 2 could be considered as lateral LNM negative, so more diagnostic approach is recommended for patients with clinicopathological and US index points >2.