A Study of the Effects of Clinicobiological Factors upon the Meningioma-Associated Peritumoral Edema Formation

ABSTRACT

It is thought that the biological aggressiveness of meningioma is closely related to the development of peritumoral edema. However, the effects of mechanical tumor factors on the venous return of underlying brain tissue, as well as those of MIB-1 or p53 immunoreactivity on the brain edema formation are still not clear. To identify factors which may influence meningioma-associated peritumoral edema development, the authors examined 28 histologically proven intracranial meningiomas(22 benign, 4 atypical, and 2 malignant meningioma patients). Correlation between the degree of brain edema and various factors including volume of the tumor, venous sinus involvements, tumor location, histologic subtypes, MIB-1 labeling index(LI), and immunoreactivity of p53 protein was analyzed retrospectively. The degree of brain edema(edema ratio) was measured by maximum edema area to maximum tumor area as seen on T2 and T1 enhanced magnetic resonance images, respectively. Mean maximum tumor area and the volume of the tumor were 15.7cm2 and 50.2cm3, respectively. The mean area of maximum edema extension was 23.3cm2 and the mean ratio between maximum edema area and tumor area was 1.90(range 0-11.5). Tumor volume and the area of edema showed significant correlation(p=0.015). MIB-1 LI, however, correlated inversely with edema ratio(p=0.039). p53 protein expression, venous sinus involvement, age, sex, and histologic characteristics did not correlated with edema area or ratio. In conclusion, this study showed there was inverse correlation between edema development and MIB-1 LI, and no correlation with p53 expression. It was thus speculated that peritumoral edema in meningioma may not be a sign of biological aggressiveness.