[Distribution of cervical lymph node metastasis in well-differentiated thyroid carcinoma]

To study the distribution of cervical lymph nodes metastases in patients with differentiated thyroid carcinoma, explore the surgical modality of the neck of cN + cervical node metastasis and evaluate the role of preoperative ultrasonography in detecting of cervical metastases of differentiated thyroid carcinoma.

Data were reviewed retrospectively from medical records between July 2003 and July 2005, in which 93 patients (113 sides) of differentiated thyroid carcinoma patients with cN + cervical lymph nodes metastasis. Patients were divided into 2 groups: group 1, 64 cervical sides with preoperative palpable cervical lymph nodes; group 2, 49 cervical sides with impalpable node but preoperative ultrasonic positive nodal metastasis. All the pathologic specimens were reviewed by pathologists counting the numbers of pathologic positive nodes and mapping localization of positive nodes in level II, III, IV, V and VI respectively.

In 93 patients 21.5% (20/93) of those metastasize bilaterally. In those 113 sides specimens 92 sides (81.4%) involved multi-sites in the neck. The distribution of metastasized nodes were; level II, 60.2% (68/113); level III, 70.8% (80/113); level IV,61.9% (70/113); level VI, 58.4% (66/113); level V, 22.5% (25/113). The numbers of positive nodes of group 1 were more than the number of group 2 (10.1 vs 6.9) and the involved levels of group 1 was also more than the levels of group 2 (3.18 level vs 2.61 level). Preoperative ultrasonography could detect 43.4% (49/113) of lymph nodes metastasis that were missed by palpation in the physical examination.

The distribution of the cervical nodes in patients with differentiated thyroid carcinoma were multi-levels in the neck and mainly localized in level II , level III, level IV and level VI. Preoperative ultrasonography is a mainstay in detecting of cervical lymph nodes metastasis in thyroid cancer. For patients with differentiated thyroid carcinoma of cN + cervical lymph nodes should be undergone modified neck dissection, includes level II, III, IV, V, VI.