Analysis of the relationship between ultrasonographic features and cervical lymph node skip metastasis of papillary thyroid micro-carcinoma

Abstract

Objective: To investigate the correlation between cervical lymph node skip metastasis with ultrasonographic characteristics of papillary thyroid micro- carcinoma (PTMC). Methods: We reviewed ultrasonographic features of 385 primary PTMC and cervical lymph node metastasis, confirmed by pathology in Tianjin Medical University Cancer Institute and Hospital, to evaluate the efficacy of ultrasonography in the diagnosis of cervical lymph node metastasis of PTMC patients. The relationship between ultrasonographic features of primary lesions and skip metastasis of cervical lymph nodes was analyzed by χ(2) test and multiple factor Cox regression. Results: Among the 385 cases of PTMC patients with cervical lymph node metastasis, 231 cases were central lymph node metastasis alone, 31 cases were lateral cervical lymph node metastasis alone, 123 cases were both central and lateral cervical lymph node metastasis. Among the 354 cases without skip metastasis of cervical lymph nodes, 48 cases were level Ⅱ, 92 cases were level Ⅲ, 83 cases were level Ⅳ, 9 cases were level Ⅴ, 354 cases were level Ⅵ. Among the 31 cases with skipping metastasis of cervical lymph nodes, 12 cases were level Ⅱ, 14 cases were level Ⅲ, 14 cases were level Ⅳ, 1 case was level Ⅴ. The sensitivity and specificity of preoperative ultrasonography in the diagnosis of central cervical lymph node metastasis were 46.3% and 66.7%, respectively, and those of lateral cervical lymph node were 91.0% and 87.8%, respectively. Univariate analysis showed that the abutment/perimeter, diameter and location of PTMC were significantly associated with skip metastasis (P<0.05), multivariate analysis showed that abutment/perimeter and location of PTMC were significantly associated with skip metastasis (P<0.05). Conclusions: The sensitivity and specificity of preoperative ultrasound diagnosis for lateral cervical lymph node metastasis of PTMC is higher than that of central metastasis. PTMC with abutment/perimeter ≥1/4 and upper portion location are prone to skip metastasis.