Microvasculature and VEGF expression in cartilaginous tumors.

ABSTRACT

We examined the microvasculature and VEGF expression in 26 cartilaginous lesions (CL) including 5 enchondromas, 9 grade 1 chondrosarcoma (CS), 6 grade 2 CS, 4 grade 3 CS, 1 mesenchymal, and 1 myxoid chondrosarcoma. The degree of neovascularization was measured by counting microvessels on H&E and factor VIII related antigen immunostained slides. Vessels were divided into pericartilage vessels (PCV) and intracartilage vessels (ICV). PVC comprised vessels around the lobules or invading the lobules but themselves surrounded by noncartilaginous stroma (ie, fibrous stroma); ICV consisted of those vessels present inside the tumoral nodules and in direct apposition with malignant cells or tumoral stroma. A direct correlation was seen between histological type and grade of CS and pericartilage vessels. In contrast, ICV were found only in higher-grade CS. No enchondromas and only 1 of 9 grade 1 CS had ICV. This patient had Ollier's disease. All but 2 of the grade 2 CS showed ICV (average, 20.5). The exceptions were predominantly grade 1 CS with focal grade 2 areas and extensive areas of necrosis. All but 1 grade 3 CS had ICV, the exception being a case of metastatic CS to the lung. Malignant chondrocytes of high-grade lesions stained strongly for vascular endothelial growth factor (VEGF), a potent angiogenic factor. The only high-grade tumors that did not express VEGF did not show ICV either. Enchondromas and grade 1 CS, most without ICV, did not express VEGE In summary, PCV are present in all categories of tumoral cartilage and the number increases with histological grade; ICV are found in high-grade lesions, and the exceptions show extensive necrosis; VEGF expression by malignant chondrocytes is seen in high-grade lesions almost exclusively, and among these in those lesions that showed intracartilage vessels. It is possible that PCV are involved in supporting tumor growth, whereas ICV might be involved in the acquisition of metastatic potential by cartilage tumors. VEGF expression is strongly associated with the presence of ICV.