MIB1 and neoplasm: In the recurrent group, nonskull base tumor location (HR 0.219; 95% CI, 0.068‐0.706; P = .011), greater extent of resection (HR 0.219; 95% CI, 0.068‐0.706; P = .011), and lower MIB‐1 labeling index (HR 0.225; 95% CI, 0.068‐0.743; P = .014) were associated with longer PFS for atypical meningiomas, while no factor demonstrated prognostic significance for OS.