Intracranial Meningioma with Leptomeningeal Dissemination : Retrospective Study with Review of the Literature

OBJECTIVE: The purposes of this article are to present 5 cases of intracranial meningioma with leptomeningeal dissemination (LD) and investigate the characteristics of this disease. METHODS: We present a retrospective case series of 5 females at our institutions (age ranged 21-72 years, mean 54.6 years) diagnosed with LD of an intracranial meningioma after surgery between 1998 and 2013. A database search revealed 45 cases with LD of meningioma in the English literature. Characteristic features were analyzed and compared. RESULTS: The incidence rate at our institutions of LD of meningioma was 0.9% (5/534). World Health Organization (WHO) grade was distributed as follows: I : 2, II : 2, and III : 1. Time to LD ranged from 2.5 months to 6.9 years; the patient with WHO grade III had the shortest interval to LD. The patient with an intraventricular meningioma (WHO grade II) had the second shortest interval to LD (1.7 years), and simultaneously revealed both LD and extraneuronal metastases. Four of 5 patients showed a disease progression, with the survival ranging from 1 month to 3.8 years after LD. Based on the literature, the initial tumor was an intraventricular meningioma in 9 patients, and their time to LD was shorter on average (mean 1.9 years). Histologically, 26 of 45 (58%) were initially diagnosed with a WHO grade II or III meningioma, and 6 of 19 patients (32%) with WHO grade I revealed malignant transformation. CONCLUSION: This study shows that intraventricular location and histologically aggressive features seem to increase the chance of LD of meningioma.