Meningioma: proliferating potential and clinicoradiological features

We examined the proliferative potentials of meningiomas in 120 patients using the MIB-1 antibody against the Ki-67 antigen and compared them with the clinicoradiological features. The Ki-67 staining index (SI) did not relate to the age and sex of the patients or the location of the tumors. Asymptomatic meningiomas showed significantly lower SIs (mean +/- standard deviation [SD], 0.87 +/- 0.56%) than symptomatic meningiomas (mean +/- SD, 1.63 +/- 2.17%). We found no relation between SIs and clinical symptoms and signs in the symptomatic meningiomas. A weak correlation was found between the size of tumors and Ki-67 SIs (r = 0.21; P = 0.024). There were significant differences in SIs between calcified (mean +/- SD, 0.77 +/- 0.41%) and noncalcified tumor (mean +/- SD, 1.75 +/- 2.25%). Diffusely calcified tumors (mean +/- SD, 0.57 +/- 0.34%) showed lower SIs than focally calcified tumors (mean +/- SD, 0.92 +/- 0.41%). Lobulated tumors showed higher SIs (mean +/- SD, 2.85 +/- 3.68%) than round tumors (mean +/- SD, 1.06 +/- 0.67%). Tumors with perifocal edema or unclear borders had higher SIs than did those without such features. Signal intensities on T1-weighted magnetic resonance images had no relation to SIs, whereas low-intensity tumors on T2-weighted images, most of which presented diffuse calcification on computed tomographic scans, showed lower SIs. This study indicates that several clinicoradiological features relate to the proliferative potential of meningiomas and that they may contribute to the management of patients.