Choroid Plexus Tumors
Choroid plexus papilloma (WHO grade I) and its malignant counterpart choroid plexus carcinoma (WHO grade III) are intraventricular papillary neoplasms derived from the choroid plexus epithelium (Aguzzi et al.2000).
These types of tumors are most commonly seen in the first 10 years of age and account for 0.4–0.6% of all cerebral tumors, 2–4% of brain tumors in children, and 10–20% of brain tumors manifesting in the first year of life. Papillomas outnumber carcinomas by a 10:1 ratio.
These tumors are most commonly found in the lateral ventricles or the fourth ventricle but may also occur in the third ventricle and the cerebellopontine angle. Lateral ventricle tumors occur primarily in children; fourth ventricle tumors are evenly distributed among all age groups.
Besides the findings of hydrocephalus, the normally well-marginated, large lobular masses present with nonspecific CT and MRI characteristics (Martin et al. 1990; Jackson et al.1992). On CT scan, the typical choroid plexus papilloma appears as a well-marginated, smooth, or lobulated isoor high-density mass protruding into the lumen of the ventricle with strong contrast enhancement.
This marked homogeneous enhancement is related to the richly vascular nature of the tumor. Tumoral calcifications are uncommon in the pediatric age group. Choroid plexus papilloma and intraventricular meningioma cannot be differentiated by CT characteristics. MRI is the method of choice for the detection and especially delineation of those intraventricular lesions.
The MRI characteristics are of intermediate signal intensity on T1-weighted and intermediate or increased signal intensity on T2-weighted images.
Both calcifications and hemorrhage may occur, and strong enhancement is typical because of the high vascularity of the lesions (Tasdemiroglu et al. 1996).
Choroid plexus papilloma can be cured surgically and has a 5-year survival rate of as much as 100%.
Choroid plexus carcinomas have a less favorable outcome and a 5-year survival rate of 40%.
- M.F. Reiser, W. Semmler, H. Hricak (Eds.) "Magnetic Resonance Tomography", Springer 2008