Cystic lymph nodes in the lateral neck as indicators of metastatic papillary thyroid cancer.

Objective: To determine whether radiographic findings portend to metastatic disease in patients with papillary thyroid carcinoma (PTC) and whether cystic lymph node metastasis can be recognized by preoperative, ultrasound-guided fine-needle aspiration (FNA).

Methods: We performed a retrospective review of patients with cystic lymph nodes in the lateral neck identified on preoperative ultrasonography between March 1996 and December 2009. Factors examined included demographic information; stage; cytologic and final pathologic findings; and imaging characteristics including location, size, and presence of vascularity and calcifications. Time of cystic node identification in relationship to initial diagnosis was also recorded.

Results: Thirty patients had cystic lymph nodes in the lateral neck on cervical ultrasonography during the study period. Among this group, 28 (93%) had PTC, 1 (3%) had papillary serous carcinoma of the ovary, and 1 (3%) had poorly differentiated thyroid cancer. Median age at initial cancer diagnosis was 41 years (range, 16-64 years). Twenty-one patients (70%) were women, and median lymph node size was 1.8 cm (range, 0.6-4.8 cm). Twenty-three patients (77%) had a solitary cystic lymph node, and the remainder had more than 1 cystic lymph node. Cystic lymph nodes were identified at initial presentation in 11 patients (37%), while cystic lymph nodes were discovered in 19 patients (63%) after the initial operation. FNA was performed on the cystic lymph nodes of 23 patients (77%). Cytologic findings were positive for metastatic disease in 18 of 23 patients (78%). Among the 5 of 23 patients with negative cytologic findings, thyroglobulin aspirate was obtained in 1 patient, confirming metastatic PTC. Final pathologic review after surgical resection of cystic lymph nodes with negative cytologic findings from FNA was consistent with metastatic disease in 4 of 5 patients (80%).

Conclusions: In patients with PTC, the presence of a cystic lymph node by ultrasonographic examination is highly suggestive of locally metastatic disease. Confirmation of metastatic PTC may sometimes be achieved with thyroglobulin aspirate from cystic lymph nodes when cytologic findings are negative. Clinicians should strongly consider surgical lymph node resection of cystic lymph nodes regardless of the preoperative cytologic findings by FNA.