The clinicopathological significance of histologic vascular invasion in differentiated thyroid carcinoma

Background: Clinicopathological correlation and clinical importance of histologic vascular invasion in differentiated thyroid carcinoma have not been fully examined. Methods: Histologic vascular invasion of 256 differentiated thyroid carcinomas was examined using Victoria-blue hematoxylin-eosin staining. Results: Vascular invasion was found in 120 patients and was independently related to lymph node metastasis (P <0.0001), extrathyroidal invasion (P = 0.0003) and differentiation (P = 0.0183). Patients with vascular invasion more frequently relapsed than those without (P = 0.0069). The disease-free survival of patients with vascular invasion (15.6 ± 1.8 years) was shorter than that of patients without vascular invasion (20.5 ± 0.9 years, P = 0.0001). In multivariate analysis, vascular invasion is an independent prognostic factor for disease-free survival, but not for overall survival. Conclusions: These data suggest that histologic vascular invasion is associated with clinicopathologically aggressive thyroid carcinomas with lymphatic and hematogenous spread and is a prognostic factor for disease-free survival.