Carcinomas usually seen only in pediatric age group.
Papillomas have characteristic lobulated gross appearance.
Most are well-differentiated and may resemble normal choroid plexus, however, anaplastic transformation may occur. Parenchymal invasion suggests carcinoma, but can be seen with benign . Calcification especially frequent in fourth ventricular tumors. In adult patients the fourth ventricle is more common. The tumor is attached to the choroid plexus.