Morphometric analysis of tumor stromal lymphatic vessels and lymphangiogenesis in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) often causes lymphatic metastasis, particularly to the regional cervical lymph nodes. Although lymphatic metastasis is closely associated with lymphangiogenesis in the tumor tissues, the detailed mechanisms are not yet fully understood. The purpose of this study was to examine the morphological association of lymphangiogenesis in the tumor stromal tissue with cervical lymph node metastases in OSCC. The medical records of 13 patients treated for OSCC affecting the tongue at the Department of Oral Surgery of Nihon University School of Dentistry at Matsudo Hospital between November 2003 and March 2011 were reviewed. The 13 cases were divided into two groups, with 7 cases in the metastasis group and 6 cases in the non-metastasis group. Histopathological (hematoxylin-eosin stain) and immunohistochemical (D2-40 antibody) examinations were performed. Lymphatic vascular density and lymphatic vascular area, lymphatic vascular morphology, and the number of lymph vessels were quantified using ImageJ software. The lymphatic vessels in the metastasis group were distributed with higher density and ran irregularly, with more remarkable deformation than those in the non-metastasis group. Cervical lymph node metastasis is one of the factors affecting progression and the prognosis of OSCC patients. In the present study, lymphatic vessels were found in the OSCC stroma, which also suggests that an increased density of lymphatic vessels leads to cervical lymph node metastases.