Angiogenesis and brain oedema in intracranial meningiomas: influence of vascular endothelial growth factor

The correlation between angiographic neovascularization, peritumoural brain oedema (PTBOe) and the expression of vascular endothelial growth factor (VEGF), was analysed in 30 patients with intracranial meningiomas. Pre-operative angiograms were examined for the existence of either an exclusively dural tumour blush or an additionally pial tumour supply from cerebral arteries. Furthermore the presence of macroscopic tumour-neovascularization and dysplastic changes of tumour-draining cerebral veins was evaluated. VEGF expression was investigated on histological tissue samples, using immunohistochemical techniques. VEGF immunohistochemistry and neuroradiological evaluations were performed in double blind fashion. Tumour volume and the amount of oedema were calculated by computerized tomography (CT) or magnetic resonance imaging (MRI). The oedema-tumour volume ratio was defined as oedema index (OeI). Compared to VEGF-negative meningiomas, tumours with striking VEGF staining revealed a significant higher mean oedema index (OeI = 4.2 vs. OeI = 1.5; p < 0.018), and a higher oedema incidence (91.7% vs. 44.4%; p < 0.046). Equally, meningiomas with additionally tumour supply from cerebral arteries were associated with a significant higher mean OeI (OeI = 4.1 vs. OeI = 1.2; p < 0.01) and oedema incidence (94.7% vs. 20.0%; p < 0.0023) than meningiomas with exclusively tumour supply from dural arteries. All meningiomas with striking VEGF-expression were associated with vascular tumour supply from cerebral arteries, but VEGF-negative tumours only in 50% (p < 0.029). These data suggest a link between VEGF-expression, arterial tumour supply and peritumoural brain oedema. The development of tumour supply from cerebral arteries may be important for formation of meningioma-related oedema. Therefore, VEGF may represent a potent mediator in the evolution of this type of vascularization in meningiomas.