Level IIb lymph node metastasis in thyroid papillary carcinoma.

The objective of the study was to evaluate the incidence of level IIb lymph node metastases in neck dissections for thyroid papillary carcinoma (TPC) patients. 47 neck dissections of 33 patients with TPC were prospectively evaluated. Selective neck dissections (levels II, III, IV, and V) were performed in all cases. If level I lymph node metastasis was suspected during the procedure, level I dissection was also performed. All level IIb specimens were sent separately from the remainder of the neck dissection for the pathological examination. The number of dissected and metastatic lymph nodes in each specimen was recorded. Twenty-two of 47 neck dissections (46.8%) were positive for the lymph node metastasis. Among 47 neck dissection specimens, the incidence of lymph node metastasis at level II was 12.7% (6 of 47) and level IIb was 2.1% (1 of 47). The rate of level IIb lymph node involvement among patients with metastatic cervical lymph nodes was 4.5% (1 of 22). The specimen with metastatic lymph node at level IIb had also metastasis at levels IIa, III, IV, and V. The results of the present study suggested that lymph node metastases in level IIb are rare in patients with TPC undergoing neck dissection.