Tumor location-dependent skip lateral cervical lymph node metastasis in papillary thyroid cancer.

BACKGROUND Lateral cervical lymph node metastasis without central lymph node (CLN) metastasis is not infrequent in papillary thyroid cancer (PTC). This study was designed to investigate the frequency and pattern of skip metastasis in PTC. METHODS We reviewed 131 patients who underwent total thyroidectomy with CLN dissection and selective lymph node dissection. Tumor location was classified in 3 areas (upper, middle, and lower third) based on preoperative ultrasonographic findings. RESULTS All skip metastases occurred in patients whose tumors had been on the upper part of the thyroid (p < .001). Among 9 patients with skip metastasis, level III lymph nodes (66.7%) were the lymph nodes that were most frequently involved in skip metastasis. CONCLUSION Primary tumors in the upper portion of the thyroid are closely linked to skip metastasis. Careful preoperative evaluation of lateral cervical lymph nodes is suggested when a tumor is in the upper portion.