Mapping the distribution of nodal metastases in papillary thyroid carcinoma: Where exactly are the nodes?

Objective: To characterize nodal disease of patients presenting with papillary thyroid carcinoma (PTC) STUDY DESIGN: Retrospective chart review.

Methods: PTC patients who underwent thyroidectomy and/or neck dissection (revision/primary) from 2004 to 2009 at a tertiary-care hospital were reviewed. Preoperative computed tomography (CT) scan and ultrasonography were utilized to identify macroscopic, clinically apparent nodal metastasis (cN+). Demographic data, type of surgery, nodal disease, and primary tumor information were recorded.

Results: Of 416 patients reviewed, 35% had cN+ on initial presentation (IP); of these, 88% and 50% had central (CND) and lateral nodal disease (LND), respectively. The presence of ectopic nodal (END) metastases (nodal disease outside typical CND or LND locations) was absent on IP but occurred in 9% of patients with nodal recurrence. END was typically found in the retropharyngeal area but also was noted in the sublingual region, subcutaneous location, axilla, and chest wall. Extrathyroidal extension (ETE) was found in 8.9% without nodal disease, 33.1% with nodal disease, and 57.1% with END (P < 0.0001). Primary tumor size greater than 4 cm (P = 0.05) was associated with nodal disease.

Conclusion: This report represents a large series describing characteristics of the primary PTC tumor and associated nodal disease not only in the central and lateral neck but also in the ectopic locations. Our results suggest that a significant proportion of patients will have nodal disease in the central compartment on IP, especially younger patients. ETE and tumor size are associated with macroscopic nodal disease (including END). Nine percent of the patients with nodal recurrence had ectopic nodes occurring in various locations, most commonly in the retropharynx. CT scan can assist with identification and surgical planning of recurrent nodal disease.

Level of evidence: 4. Laryngoscope, 127:1959-1964, 2017.