Paediatric Radiology

A 9-year-old male presents with headaches and vomiting. Papilloedema was noted on clinical examination. MRI brain has been performed. 
What is the diagnosis?

__________SCROLL FOR ANSWER__________

Findings

Findings reveal an intra-ventricular mass lesion, in the atria of the right lateral ventricle with intermediate signals on T1 and T2 W images. Curvilinear areas of signal void are seen, indicating tumoral vessels. Obstructive hydrocephalus is noted.

Diagnosis

Choriod Plexus Papilloma

Discussion

Introduction

Choroid plexus papillomas are rare tumors of neuroectodermal origin, representing 0.5 to 0.6% of all intracranial neoplasms. 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.

Imaging Findings

On CT scan the typical choroid plexus papilloma appears as a well marginated, smooth or lobulated iso- or high-density mass protruding into the lumen of the ventricle with strong contrast enhancement. This marked homogeneous enhancement is related to the highly vascular nature of the tumor. Tumoral calcifications are uncommon in the pediatric age group.

The MRI characteristics are intermediate on T1- and intermediate or increased signal intensity on T2-weighted images. 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.