Differences in the characteristics of papillary thyroid microcarcinoma ≤5 mm and >5 mm in diameter.

BACKGROUND The behavior and optimal management of papillary thyroid microcarcinomas (PTMCs) after thyroidectomy remain unclear. The purpose of this study was to compare the clinicopathologic features and tumor recurrence rates of patients with PTMCs ≤5 mm and >5 mm in diameter after total thyroidectomy. METHODS A group of patients with PTMCs ≤5 mm (n=83) has been compared to a group with >5 mm (n=122). All of these patients had conventional type PTMCs and were followed up for 5 years. Both the histology and the outcome have been compared. RESULTS Sex (p=.014) and extrathyroidal extension (p=.003) of patients in the ≤5 mm and >5 mm groups differed significantly. Two and 5 patients from these groups, respectively, experienced tumor recurrence within 5 years (2.4% vs 4.1%; p=.634). CONCLUSION The clinicopathologic features of PTMCs ≤5 mm and >5 mm are similar, except for sex distribution and extrathyroidal extension. The 5-year recurrence rate in the 2 groups did not differ significantly.