Occult Contralateral Central Lymph Node Metastases in Papillary Thyroid Carcinoma with Unilateral Lymph Node Metastasis in the Lateral Neck

The frequencies, pattern, and predictive factors for occult contralateral central lymph node (LN) metastases in papillary thyroid carcinoma (PTC) patients with unilateral lateral neck metastases are still unsettled.We reviewed the medical records of 70 consecutive PTC patients with unilateral positive lateral neck who have initially received total thyroidectomy and comprehensive neck dissection including bilateral central LN dissection. The relationships between occult LN metastases to the contralateral central neck compartment and preoperative image findings and clinicopathologic factors were analyzed.Central neck LN metastases were present in 82.9%, in which 34.3% had bilateral central neck involvement and 48.6% had unilateral ipsilateral central neck involvement. Isolated contralateral central LN metastases without ipsilateral central LN metastases were not found. Multivariate analysis showed that the multifocality of primary thyroid tumor (p = 0.010, odds ratio = 5.120) and the presence of metastases in all lateral neck levels (p = 0.017, odds ratio = 5.130) were independent risk factors for the presence of contralateral central LN metastases.The rate of occult contralateral central LN metastases was relatively high (34.3%) in PTC with ipsilaterally positive lateral neck, and multifocal primary tumor and positive LN involvement in all lateral neck levels are associated with contralateral central LN metastases.