They occur predominantly in the first decade of life, especially in the first two years. Choroid plexus papillomas bulge into the ventricular cavity and are therefore primarily intraventricular. The most common site of origin in the pediatric age group is within the atria of the lateral ventricles, and in adults within the fourth ventricle. These tumors usually do not invade the brain. This marked homogeneous enhancement is related to the highly vascular nature of the tumor.
Tumoral calcifications are uncommon in the pediatric age group.
There may be areas of internal signal void, predominantly curvilinear, indicating enlarged intratumoral vessels. MRI is superior to CT in assessing intraventricular location and extension of the tumor.