목적: The impact of minimal extrathyroidal extension (mETE) on the prognosis of patients with papillary thyroid carcinoma (PTC) is controversial. In this study, we investigated whether minimal ETE (mETE) is related to the aggressive biology of metastatic lymph nodes (LNs) in patients with PTC. 방법:We conducted a retrospective review of 369 patients who had biopsy- confirmed cervical LN metastasis after initial surgery for PTC. We analyzed the relationship between metastatic LN size, number, LN ratio and presence of extranodal extension (ENE) as features of metastatic LNs and aggressive biology. The correlation between clinicopathologic factors and the primary tumor to the features of metastatic LNs were statistically analyzed. 결과:Size of the primary tumor (> 1 cm) had an independent correlation to mETE (p<0.001, HR=5.750). While mETE was related to number of metastatic LNs (> 5, p=0.002), LN ratio (> 0.31, p=0.012) and ENE (p<0.001) in univariate analysis, only ENE (p=0.004, HR=2.322) was independently correlated to mETE in our series. Along with mETE, size of the primary tumor (> 1 cm) had significant impact on ENE (p=0.013, HR=2.107). 결론:Minimal ETE may be a presentation of aggressive biology of the primary tumor reflected by ENE of metastatic LN in patients with PTC. Thus, mETE, particularly when combined with larger primary tumor (> 1 cm), may be a significant factor determining the management of cervical LNs in patients with PTC.