The relevance of angiogenesis in benign and malignant epithelial tumors of the ovary: a quantitative histologic study.

The ability of a tumor to grow and eventually to infiltrate adjacent tissues requires a sufficient blood supply. Many malignant neoplasms have been shown to induce neovascularization. We asked whether it is possible to characterize ovarian epithelial tumors on the basis of vascularization and whether vascularization can be used to differentiate between benign and malignant neoplasms. We examined 14 cases of benign cystadenomas and 18 carcinomas. The microvessels were identified by immunohistochemical staining of endothelial cells for factor VIII. They were counted within the most vascular area of a tumor (neovascular "hot spot") on a x 100 and a x 400 field. Mean vessel counts were 51.64 [standard error of the mean (SEM), 5.7] in the benign cystadenomas and 131.05 (SEM, 6.7) in the group of carcinomas at a x 100 magnification. The mean microvessel counts per x 400 field were 14.4 (SEM, 1.9) in the benign and 33.7 (SEM, 3.45) in the malignant tumors investigated. These differences were significant (t test for independent samples, P < 0.001). Since our study shows significantly fewer small blood vessels in the benign cystadenomas than in the malignant tumors, the histologically determinable vascular density may be the basis for imaging blood flow by means of color ultrasound.