"Intraventricular meningiomas are thought to arise from meningothelial inclusion bodies located in the tela choroidea and/or mesenchymal stroma of the choroid plexus 5,6,7. In general, these meningiomas are most commonly of the fibrous meningiomas 5."
"Intraventricular meningiomas are rare tumours usually encountered in adults and are somewhat distinct from the far more common extra-ventricular meningioma."