Immunohistochemical Study of Vasculogenic Mimicry and Angiogenesis in Melanocytic Tumors of the Eye and the Periocular Area

BACKGROUND/AIM: The ability of a tumor to grow requires a sufficient blood supply. Microvascular density is considered the standard for assessing the neovasculature. Tumor cell vasculogenic mimicry refers to the formation of tumor cell-lined vessels that contribute to tumor neovascularization. The aim of the present work was to study angiogenesis and vasculogenic mimicry in benign and malignant melanocytic tumors of the eye and the periocular region. PATIENTS AND METHODS: Histological sections from 118 patients were studied. Eighty-eight of the patients had nevi while the remaining 30 had malignant melanomas. Microvascular density was assessed by using antibodies against the endothelial cell markers CD31 and CD34. Vascular-like channels between neoplastic cells, that were not lined by endothelial cells and thus were negative for CD31 and CD34, represented areas of vasculogenic mimicry. RESULTS: Angiogenesis was more pronounced in melanomas compared to melanocytic nevi and was increased in melanomas with high mitotic index and/or epithelioid cell preponderance compared to melanomas with low mitotic index and/or spindle cell predominance. Vasculogenic mimicry was observed in many melanomas, while it was evident in the minority of benign nevi as well. CONCLUSION: The existence of vasculogenic mimicry in benign nevi might have prognostic implications.