Comparing the Surface Area of Looping Vasculogenic Mimicry Patterns With the Surface Area of Blood Vessels

Abstract

Purpose: : Laminin–rich looping vasculogenic mimicry patterns are detected in tissue sections of aggressive primary uveal melanomas and their metastases. These looping patterns transmit fluid in vitro and in vivo and, together with blood vessels, contribute to the perfusion of uveal melanomas. We compared the surface areas of looping vasculogenic mimicry patterns with the surface area of blood vessels in highly vascularized metastatic uveal melanoma tissues.

Methods: : Serial sections of highly vascularized metastatic melanoma to the liver containing looping vasculogenic mimicry patterns were dual–labeled with fluorescent–tagged antibodies to CD34 and laminin. The areas of greatest microvascular density were identified by laser scanning confocal microscopy, and three dimensional volumes of these regions were constructed using an immersive three–dimensional environment. The ratio of the surface area of looping vasculogenic mimicry patterns to blood vessels was calculated.

Results: : In metastatic uveal melanoma tissues featuring co–localization of high microvascular density and vasculogenic mimicry patterning, microvascular density was high [66.4 microvessels adjusted for 0.313 mm² area (range 56.7–72.7)]. The surface area of vasculogenic mimicry patterns was 11.6 fold greater (range 10.8–14.1) than the surface provided by CD34–positive blood vessels.

Conclusions: : Looping extravascular matrix patterns of vasculogenic mimicry provide a potentially larger surface for tumor perfusion than tumor blood vessels.

Keywords: melanoma • pathology techniques • microscopy: light/fluorescence/immunohistochemistry