To study the correlation between the sonographic features of papillary thyroid microcarcinoma (PTMC) and high volume lymph node metastasis.

Medical records of 463 PTMC patients were reviewed. Cases of all patients are completed with lymph node metastasis identified by histopathology. Sonographic features such as lesion number, lesion size, echogenicity, calcification, envelope and vascularity of papillary microcarcinoma are recorded. Univariate and multivariate analysis was performed to investigating relationship between sonographic features and high volume lymph node metastasis.

Twenty four patients have high volume central lymph node metastasis (5.2%, 24/463), in univariate analysis, sex (11.2% in male vs 3.4% in female), age (8.3% in <45 years vs 2.4% in ≥45 years) , calcification (8.3% in micro vs 0.0% in coarse, 3.2% in mixed and 0.7% in non) , extracapsular invasion (9.3% with vs 3.2% without) and size (9.2% in ≥7 mm vs 2.5% in <7 mm) showed significant difference; multiple logistic regression analysis showed that male (OR=3.205, P=0.009) , age<45 years (OR=2.923, P=0.031), microcalcification (OR=9.380, P=0.031) and tumor size≥7mm (OR=3.272, P=0.013) is independent risk factor for high volume lymph node metastasis in the central compartment of PTMC. 10 patients have high volume lateral lymph node metastasis (2.2%, 10/463), in univariate analysis, age (4.1% in <45 years vs 0.4% in ≥45 years), number of lesions (5.3% in multiple vs 0.9% in single) showed significant difference; multiple logistic regression analysis showed that age<45 years (OR=11.939, P=0.024) and multiple lesion (OR=7.247, P=0.007) is independent risk factor for high volume lymph node metastasis in the lateral compartment of PTMC.

Sonographic features of primary papillary microcarcinoma of the thyroid has correlation with high volume lymph node metastasis.