Lateral peritumoral lymphatic vessel invasion can predict lymph node metastasis in esophageal squamous cell carcinoma

Lymph node metastasis is an important prognostic factor in many types of cancer. We investigated the clinical significance of lymphangiogenesis and lymphatic vessel invasion in esophageal squamous cell carcinoma. We evaluated lymphatic vessel density and lymphatic vessel invasion in the intratumoral, peritumoral and normal compartments using D2-40 immunostaining. In addition, the peritumoral compartment was divided into the lateral peritumoral compartment and the non-lateral peritumoral compartment. The lymphatic vessel density was higher in the peritumoral and intratumoral compartments than in the normal compartment. However, the lymphatic vessel density did not correlate with any pathological parameters including lymph node metastasis. Intratumoral and peritumoral lymph vessels were small and collapsed while normal lymphatic vessels and lymphatic vessels with lymphatic vessel invasion were dilated and large. The presence of lymphatic vessel invasion, in the lateral peritumoral compartment but nowhere else, significantly correlated with lymph node metastasis. These results suggest that lymphangiogenesis might occur with esophageal cancer, but it does not play a direct role in lymphatic vessel invasion and lymph node metastasis. Peritumoral lymphatic vessel invasion, especially in the lateral peritumoral compartment, should imply a high probability of regional lymph node metastasis.