EPENDYMOMAS

In common with their cell of origin, ependymomas are found throughout the central nervous system, from frontal horns to filum terminale. Intracranially, most occur in the fourth ventricle of children, although supratentorial neoplasms appear in both children and adults. The spinal lesions, especially those of the filum terminale, are usually seen in adults. A rare neoplasm arises as a primary tumor in sacral soft tissues or bone... The intracranial lesions meet little resistance to intraventricular expansion and can become sizable exophytic masses before the onset of obstructive symptoms. Such neoplasms are lobular, well circumscribed, and often broadly attached to the ventricular floor from which they arise. Secondary adhesions to other ventricular surfaces may also form. Occasional supratentorial lesions arise superficially, seemingly remote from the ventricular system. Characteristically, in the fourth ventricle, there is little invasion of the ventricular wall, and but for their..