Third ventricle meningioma
The most common site for intraventricular tumors is the lateral ventricle. The third ventricle is rarely the primary site of origin. Often, due to the large size of these tumors, it becomes very difficult to ascertain the exact site of origin. These tumors are divided into anterior third ventricular meningiomas without dural attachment, which may arise from the tela choroidea in the roof or rarely from the floor of the third ventricle, and posterior third ventricular tumors arising from the posterior tela choroidea and the tenia fornicis in the velum interpositum.