The role of angiogenesis in vulvar cancer, vulvar intraepithelial neoplasia, and vulvar lichen sclerosus as determined by microvessel density analysis.

Objectives: We compared microvessel density (MVD) in normal, benign, preneoplastic, and neoplastic (squamous cell carcinoma (SCC)) vulvar disease to ascertain if this parameter could identify cases with lichen sclerosus (LS) and high-grade vulvar intraepithelial neoplasia (VIN3) at risk of developing malignancy.

Methods: Microvessels were immunohistochemically stained in paraffin wax-embedded vulvar tissue sections with anti-von Willebrand factor (vWF) antibody using the streptavidin-biotin-horseradish peroxidase complex technique. Three "hot spots" with the greatest MVD were identified within 200 microm of the subepithelial dermis under low magnification (x 40 and x 100). The highest (HVD) and average (AVD) MVDs were quantified for each sample under high magnification (x 200) using an image analysis system.

Results: HVD and AVD showed similar significant differences. SCC had significantly the highest MVD followed by VIN3, normal vulva, and LS. LS had significantly the lowest MVD, even lower than that of normal vulva. Two cases of VIN3 had much higher HVD (9.16 and 9.61) and AVD (6.89 and 7.71) compared with the main cluster of cases.

Conclusion: In vulvar LS, MVD, as assessed by HVD/AVD, is not a useful parameter in determining potential malignant progression, while in VIN3 this parameter could be valuable in identifying cases at greatest risk of progression to invasive disease.