Lateral cervical lymph node metastases from papillary thyroid carcinoma: pattern of nodal metastases and optimal strategy for neck dissection.

BACKGROUND: The pattern of lateral cervical metastases from papillary thyroid carcinoma (PTC) has been reported without a clear understanding of the distribution of central nodes at risk. The present study evaluated the pattern of central and lateral cervical metastases from PTC with respect to recently defined neck sublevels and subsites.
METHODS: Between 2003 and 2006, 52 consecutive patients with lateral cervical metastases from previously untreated PTC underwent total thyroidectomy and therapeutic comprehensive neck dissection of the central and lateral compartments, including five bilateral neck dissections. Neck dissection specimens were separately obtained for analyzing lymph node involvement with respect to neck sublevels and subsites.
RESULTS: For the lateral compartment, 75.9% of cases showed metastatic disease at level IV, 72.2% at IIa and III, 16.7% at IIb, 13.0% at Vai, 3.7% at Ib and Vb, and 0% at Vas. For the central compartment, 84.6% of cases showed metastatic disease at the ipsilateral paratracheal nodal site, 46.2% at the superior mediastinal, 30.8% at the pretracheal, and 8.9% at the contralateral paratracheal site. Forty-six of 57 lateral neck dissection samples (80.7%) showed multilevel disease, and skip lateral metastasis was found in five patients (9.6%). Level I and V involvements were always associated with multilevel disease.
CONCLUSIONS: Lateral cervical metastasis from PTC is commonly associated with multilevel disease and central nodal involvement. Neck dissection including ipsilateral central and lateral compartments may be the optimal treatment for these patients.