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

Objective: 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.

Methods: 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.

Results: 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 <80 (P < 0.001), tumor size ≥5 cm (P = 0.015), tumor size (per-centimeter increase) (P = 0.022), bone invasion (P = 0.004), a history of surgery (P < 0.001), and subtotal resection (P = 0.009) were associated with worse progression-free survival. Male gender (P = 0.039), tumor size (per-centimeter increase) (P = 0.043), bone invasion (P = 0.030), and a history of surgery (P = 0.007) were associated with poor overall survival.

Conclusions: This study showed that gross total resection should be achieved in grade II meningiomas. Patients with larger tumors and/or surgical histories had worse outcomes.