Clinical Relevance and Management of Recurrent Laryngeal Nerve Inlet Zone Lymph Nodes Metastasis in Papillary Thyroid Cancer

Abstract

BackgroundRecurrent nodal disease often occurs in recurrent laryngeal nerve inlet zone (RLNIZ), leading to difficult surgical management.MethodsMedical records of 947 patients with PTC and 33 patients with recurrent PTC were retrospectively reviewed. Totally 169 sides of RLNIZ dissection in 152 patients (17 cases were bilateral and 135 cases were unilateral) with primary surgery and 4 patients with structural recurrent disease were included for the analysis.ResultsThe rate of lymph node metastasis in RLNIZ was 31.3% (47/150). The incidence of transient hypoparathyroidism was 5.9% and no RLN injury and permanent hypoparathyroidism occurred. RLNIZ lymph nodes metastasis (LNM) was significantly associated with age <45 years, larger tumor size, number of CNLNM, and lateral node metastasis. CNLNM and lateral node metastasis were independent risk factors for RLNIZ LNM. Recurrent nodal disease in RLNIZ was identified in four of 33 patients and permanent recurrent laryngeal nerve (RLN) injury was observed in one of four patients.ConclusionLymph nodes in RLNIZ are usually involved in patients with heavy tumor burden and can be removed safely at initial surgery. Once central or lateral LNM was confirmed preoperatively or intraoperatively, RLNIZ lymph node dissection should be carefully performed to reduce the rate of structural recurrence in the central compartment.

Predictive factors and risk analysis of recurrent laryngeal nerve invasion in papillary thyroid carcinoma ≤ 1 cm

“…Similar to the results of Zheng and cols. (28), more evidence is needed to support the correlation between the vertical location of the tumor and RLN invasion in current study; while RLN invasion was much commonly presented in cases where tumor located on the dorsal side of thyroid gland as compared to those on the ventral side, which indicated that features of posterior tumor should be given more attentions to the possibility of RLN invasion, even in the absence of VCP (29).…”

“…In addition to extrathyroidal extension, some cases in this study exhibited other aggressive behaviors, for example LNM ( 33 ). The LNM in thyroid cancer often occurs in the central neck, so that RLN could also be infiltrated ( 28 ). More importantly, a fair number of patients suffered asymptomatic RLN invasion by LNM until detected in thyroid surgery ( 8 ).…”