Ultrasonography is valuable in evaluation of papillary thyroid microcarcinoma based on 5 mm tumor size.

INTRODUCTION

Fine-needle aspiration was once done in suspected malignant thyroid nodules more than 5 mm in diameter. Five millimeter has been applied in many studies as the cut off tumor size in recent years. In this study, we would like to analyze the clinicopathological and ultrasonographic features of papillary thyroid microcarcinoma (PTMC) ≤5 mm and >5 mm with the aim of finding out the diagnostic value of ultrasonography.

SUBJECTS AND METHODS

A total of 291 patients from January 2012 to October 2014 who underwent an ultrasound examination and were postoperatively diagnosed as PTMC were enrolled in the study. The patients were divided into Group A (≤5 mm) and Group B (>5 mm, ≤10 mm) based on diameter. The clinicopathological and ultrasonographic features of the two groups were statistically analyzed.

RESULTS

In total, 291 thyroid tumors were analyzed in 291 patients. In patients who were identified with multiple tumors, the largest nodule in size was used for analysis. PTMC >5 mm in diameter were found with a higher incidence of lymph node metastasis and advanced tumor-node-metastasis (TNM) Stage (III/IV) with a significant difference, also with a larger part of multiple tumors compared to PTMC <5 mm. Of all the ultrasonographic features studied, calcification and peripheral halo were more significantly correlated with PTMC >5 mm. The presence of vascularity and blood supply were both associated with the tumor size.

CONCLUSION

Larger tumor size of PTMC is more likely to involve in lymph node metastasis and advanced TNM stage. Correlation of tumor size with calcification, peripheral halo, vascularity, and blood supply do exist in PTMC. Ultrasound is of great value in the evaluation of PTMC.