Solitary lateral neck node metastasis in papillary thyroid carcinoma

Background: Papillary thyroid carcinoma (PTC) is associated with a high incidence of regional node metastasis, but the patterns of lateral neck node metastasis (LNM) vary. Occasionally, a solitary LNM (SLNM) is seen in PTC patients. We therefore assessed whether selective single level node dissection is appropriate in PTC patients with SLNM.Methods: We retrospectively reviewed the medical records of 241 PTC patients who underwent total thyroidectomy with central neck dissection plus ipsilateral internal jugular node dissection (level II to IV) between January 2010 and December 2011. Of these patients, 51 had SLNM and 190 had multiple LNM (MLNM). The clinicopathologic characteristics of the two groups were compared.Results: Age, gender ratio, and numbers of lateral neck nodes harvested (29.4 ± 11.0 versus 30.3 ± 9.5; P = 0.574) were similar in the SLNM and MLNM groups. Mean primary tumor size was significantly smaller in the SLNM than in the MNLM group (1.03 cm versus 1.35 cm; P = 0.037). The proportion of patients with primary tumor ≤ 1 cm was significantly greater in the SLNM group (60.8% versus 38.4%; P = 0.006), whereas the proportion with maximal node size ≤ 0.7 cm (28.9% versus 73.3%; P <0.001) and the proportion with capsular invasion (62.7% versus 83.7%, P = 0.002) were significantly lower in the SLNM than in the MLNM group.Conclusions: Selective single level neck dissection can be considered as an alternative to systemic lateral neck dissection in PTC patients with SLNM, maximal metastatic node size ≤ 0.7 cm, and no extrathyroidal invasion.