Peritumoral brain edema associated with meningioma

BACKGROUND: The extent of peritumoral brain edema (PTBE) associated with meningiomas is very variable. Many causative factors have been investigated, but the mechanism of PTBE associated with meningioma has been unclear until now. Recently, the cerebral-pial blood supply and vascular endothelial growth factor (VEGF) have been implicated as causative factors of PTBE. METHODS: Seventy-three supratentorial meningiomas were investigated to identify factors, including type of arterial blood supply and VEGF expression, that may influence the development of meningioma-associated PTBE. The type of arterial blood supply was defined by the selective angiography. Paraffin embedded tumor sections were stained with monoclonal VEGF antibody by an immunoperoxidase method. The extent of PTBE was estimated by using preoperative magnetic resonance imaging as an edema index (EI). RESULTS: Forty-six meningiomas demonstrated PTBE, and the other 27 did not. Multiple regression analysis revealed close correlation between PTBE and type of arterial supply (P = 0.004), size of tumor (P = 0.021), vascular density (P = 0.028), and VEGF expression (P = 0.046). In meningiomas with cerebral-pial supply, the EI had increased significantly, just as VEGF was strongly expressed (P < 0.001). In contrast, meningiomas without a cerebral-pial supply developed little or no PTBE and less VEGF expression. CONCLUSIONS: The current results suggest that VEGF expression contributes to PTBE formation in meningioma only when a cerebral-pial blood supply exists.