Purpose
Total thyroidectomy (TT) with level VI and VII central neck dissection is the initial treatment for medullary thyroid carcinoma
(MTC) without identifiable neck metastasis. Level II to V lateral neck dissection is performed if neck metastasis is present
or suspected. We conducted this study to identify the frequency and clinical determinants of skip neck metastasis in MTC.
Methods
We reviewed the medical records of 32 patients who underwent TT and bilateral neck dissection for MTC. The clinical features
were correlated with pN status in the central versus lateral compartments of the neck.
Results
Neck lymph node metastasis (pN+) was found in 20 patients (62.5%) and skip metastases were found in 7 (35%) patients. The
sensitivity of the pN status of the central compartment of the neck to predict the pN status of the lateral compartment of
the neck was 53.8% and specificity was 63.2%. We found pN+ in 90% of the patients with lymph nodes >15 mm in diameter versus
50% in those with lymph nodes <15 mm in diameter.
Conclusions
There is skip metastasis in MTC. It is unsafe to use the lymph node status of the central compartment of the neck to define
the pN status of the lateral neck. A lymph node greater than 15 mm in diameter is related to pN status.
Key words Thyroid neoplasm - Medullary carcinoma - Medullary surgery - Lymph node metastasis - Neck dissection
This paper was presented as a lecture at the 6th International Conference on Head and Neck Cancer 2004 in Washington, USA.