Cystic Lateral Lymph Node Metastases From Papillary Thyroid Cancer Patients

Objectives/Hypothesis Papillary thyroid carcinoma (PTC) tends to metastasize rather early to local lymph nodes (LNs). Incidences of cystic LN metastases is relatively rare compared with that of solid LN metastases. Few studies have attempted to assess the characteristics in these patients. This study aimed to compare the clinicopathologic characteristics and surgical outcomes between patients with cystic LN metastases and those with solid LN metastases. Study Design Retrospective cohort study. Methods We retrospectively reviewed the data of 1,028 patients with N1b PTC who underwent bilateral total thyroidectomy with central compartment neck dissection and modified radical neck dissection between January 2005 and September 2011. Of these, 136 (13.2%) had cystic LN metastases and 892 (86.8%) had solid LN metastases. Clinicopathologic characteristics and surgical outcomes were compared between these two patient groups. Results The proportion of patients with thyroid tumor multifocality was relatively higher in the cystic node cohort (19.9% vs. 12.7%,P= .048). The number of total metastatic LNs and positive lateral LNs was slightly higher in the cystic node cohort (11.3 +/- 8.9 vs. 9.7 +/- 7.5,P= .029 and 6.9 +/- 6.3 vs. 5.5 +/- 4.6,P= .018, respectively). The proportion of patients with recurrence was higher in the cystic node cohort (14.0% vs. 3.0%,P < .001). Multivariate analysis indicated that cystic nodes were a significant risk factor for recurrence (hazard ratio: 5.265, 95% confidence interval: 2.898-9.563). Conclusions This study demonstrates that cystic lateral LN metastases are associated with aggressive tumor behavior in PTC patients. and that their presence is a significant independent prognostic factor for disease-free survival. Level of Evidence 2bLaryngoscope, 2020