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. Hydrocephalus may reflect multiple factors, including CSF over-production, ventricular obstruction, and impaired CSF reabsorption. Can present as a congenital neoplasm.