Lateral lymph node metastasis in papillary thyroid carcinoma: results of therapeutic lymph node dissection.
BACKGROUND
Cervical lymph node metastases are quite common in papillary thyroid cancer (PTC) and they usually spread in a contiguous fashion. However, "skip metastasis," defined as lateral lymph node metastasis without central lymph node metastasis, also occurs in patients with PTC. There is little information regarding skip metastasis in papillary thyroid microcarcinoma (PTMC). The goal of this study was to determine the prevalence and associated clinical and imaging features of skip metastasis in PTMC.


METHODS
We performed a retrospective study of 245 patients with PTMC who underwent either thyroidectomy and central lymph node dissection or thyroidectomy, central lymph node dissection, and lateral lymph node dissection if preoperative ultrasonography or computed tomography suggested lateral node metastasis. Clinicopathologic results were reviewed, and the patterns of cervical lymph node metastasis were analyzed.


RESULTS
Cervical lymph node metastases were present in 26.5% of cases. The frequency of lymph node metastases was 21.8% in the group that only had thyroidectomy and central lymph node dissection and 51.3% in the group that had thyroidectomy, central lymph node dissection, and lateral lymph node dissection. Younger age, larger tumor size, multiplicity, bilaterality, encapsulation, extrathyroid extension, and lymphatic invasion were associated with metastasis to nodes in the central or lateral compartment. Lateral lymph node dissection was performed in 15.9% of patients. Skip metastasis was observed in 7.7% of the cases in which combined central and lateral node dissection was performed. No features of the primary thyroid tumor could be associated with the development of skip metastasis.


CONCLUSIONS
Skip metastases occur in a minority of patients with PTMC. We recommend, therefore, that preoperative studies in patients suspected of having PTMC focus not only on nodes in the central compartment but also lateral cervical nodes since the information obtained would guide the extent of surgery.
Chung
Yoo Seung
YS
Department of Surgery, College of Medicine, The Catholic University of Korea, Seoul, Korea.
Kim
Jee Young
JY
Bae
Ja-Seong
JS
Song
Byung-Joo
BJ
Kim
Jeong Soo
JS
Jeon
Hae Myung
HM
Jeong
Sang-Seol
SS
Kim
Eung Kook
EK
Park
Woo-Chan
WC
D000328:Adult; D000368:Aged; D002291:Carcinoma, Papillary / Q000473:pathology* / Q000556:secondary* / Q000601:surgery; D005260:Female; D006801:Humans; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000473:pathology* / Q000601:surgery; D008207:Lymphatic Metastasis / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013960:Thyroid Function Tests; D013964:Thyroid Neoplasms / Q000473:pathology* / Q000556:secondary* / Q000601:surgery; D013965:Thyroidectomy; D014057:Tomography, X-Ray Computed; D055815:Young Adult