• Korean Journal of Head & Neck Oncology
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• v.31 no.2
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• pp.6-10
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• 2015

Background and Objective : Papillary thyroid microcarcinoma(PTMC) is known as slow growing cancer with good prognosis. However, extrathyroidal extension may increase the risk of cervical lymph node metastasis and local invasion to surrounding structures. The aim of this study was to assess the characteristic features of the tumor invading the posterior thyroid capsule. Material and Methods : We made a retrospective review of 123 PTMC patients with thyroid capsule invasion, pathologically staged as T3 or T4. 74 patients (60.2%) had invasion to posterior thyroid capsule (group A) while 49 patients (39.8%) had invasion to-anterior thyroid capsule or anterior wall of trachea (group B). We assessed the clinicopathologic factors of the patients according to the location of capsular invasion of PTMC. Results : There was no difference regarding age, gender, T and N classification and incidence of lymph node metastasis between two groups. Local invasion rate to recurrent laryngeal nerve was 6.8% in patients with posterior thyroid capsule invasion, while the incidence was zero in those with capsular invasion to other locations Conclusion : Increased risk of local invasion to the recurrent laryngeal nerve should be considered in patients with PTMC presenting invasion of the posterior capsule.