Prognostic Factors, Survival, and Treatment for Intracranial World Health Organization Grade II Chordoid Meningiomas and Clear-Cell Meningiomas

Chordoid meningioma (CM) and clear-cell meningioma (CCM) are rare World Health Organization grade II meningioma subtypes. This study aimed to evaluate favorable factors and appropriate therapeutic strategies for these lesions. We retrospectively reviewed clinical data from 111 cases of grade II meningiomas, including 55 cases of CM and 56 cases of CCM, between January 2011 and December 2015. The mean follow-up time of the rare World Health Organization grade II meningiomas (n = 111) was 45.3 months. In the CM group, 8 patients (14.5%) experienced recurrence, and 2 patients (3.6%) died. In the CCM group, 22 patients (39.3%) experienced recurrence, and 9 patients (16.1%) died. Significant differences were observed between the CM and CCM groups in tumor size (P = 0.019), history of surgery (P = 0.038), and peritumoral edema (P = 0.004). In the CM group, gross total resection was associated with favorable progression-free survival (hazard ratio, 0.144; 95% confidence interval, 0.029–0.714; P = 0.018). In the CCM group, univariate analyses showed that preoperative Karnofsky Performance Status