Intracranial Clear Cell Meningiomas: Study on Clinical Features and Predictors of Recurrence.

OBJECTIVE: Clear cell meningioma (CCM) is a rare histologic subtype of meningioma that is classified as World Health Organization grade II tumor. We conducted the present study to characterize clinical features of intracranial CCM and investigate the prognostic factors associated with surgical recurrence-free survival of the patients.

METHODS: PubMed and Embase were searched for case reports and series relevant to CCM. For each included study, relevant data were extracted, including patients' characteristics, pathology findings, therapeutic modality, and outcome.

RESULTS: A total of 146 intracranial CCMs patients were included, comprising 73 females and 73 males. The median age of the patients at surgery was 32 years. Most tumors (58.2%) were located in the skull base region. Ninety-nine (67.8%) patients underwent gross total resection (GTR), and 47 (32.2%) patients underwent subtotal resection (STR). Seventy-four (50.7%) patients had tumor recurrence during the follow-up. Recurrence-free survival rates at 1 and 5 years after resection were 86% and 37%, respectively. Multivariate analysis showed that STR (hazard ratio [HR], 4.13; P < 0.001) and male gender (HR, 1.69; P = 0.030) were associated with increased recurrence while postoperative radiotherapy (HR, 0.51; P = 0.040) was related to decreased recurrence.

CONCLUSIONS: The results suggest that intracranial CCM has its own unique clinical features compared with the other 2 types of grade II meningiomas. Patients with subtotally resected tumors, males, or those who did not receive postoperative radiotherapy are at greater risk of recurrence. GTR should be the primary goal in the surgical management of intracranial CCMs. Our data also highlight the value of radiotherapy in intracranial CCM patients.