Assessment of vascularity in common blue nevi, small/medium congenital nevocellular, common and dysplastic acquired melanocytic nevi and melanomas: a comparative study.

Angiogenesis and vascularity are researched in melanocytic tumors for their importance in carcinogenesis. For the first time, to the best of our knowledge, the authors compared the microvascular characteristics between small/medium congenital nevocellular nevi (CN), common blue nevi (BN), common and dysplastic acquired melanocytic nevi (AMN), and melanomas. The authors collected 31 BN, 48 CN (≤5 cm), 35 AMN (14 common, 21 dysplastic), and 26 melanomas. Vessels were stained with factor VIII. Microvascular density (MVD) and total vascular area (TVA), where evaluated in high capillary density areas. Student t and Mann-Whitney tests were used. MVD (mean ± SD) was low in BN (3.52 ± 1.21) and significantly higher in CN (7.56 ± 2.47) (P < 0.001). TVA was low in BN and significantly higher in CN (Mann-Whitney U = 141, n1 = 48, n2 = 31, P < 0.001, 2-tailed). MVD was not significantly different between common and dysplastic AMN (20.64 ± 7.87 and 20.38 ± 9.54, respectively) (P > 0.05). TVA was not significantly different between common and dysplastic AMN (Mann-Whitney U = 164, n1 = 14, n2 = 21, P > 0.05, 2-tailed). MVD was significantly lower in CN (7.56 ± 2.47) compared with AMN (20.49 ± 8.79) (P < 0.001). TVA was significantly lower in CN compared with AMN (Mann-Whitney U = 1486, n1 = 48, n2 = 35, P < 0.001, 2-tailed). MVD was significantly lower in AMN (20.49 ± 8.79) compared with melanomas (33.77 ± 14.32) (P < 0.001). TVA (mean ± SD) was significantly smaller in AMN (18473.94 ± 7050.61) compared with melanomas (29308.50 ± 11307.22) (P < 0.001). Vascularity increased from BN to CN to AMN with melanomas being the most vascular. Common and dysplastic AMN had comparable vascularity. The implications of our results regarding melanoma transformation risk are considered.