Colloid cyst of the third ventricle associated with anterior cerebral artery trifurcation and agenesis of the corpus callosum: findings on MRI and CT angiography.

We report MRI with diffusion-weighted imaging, and multidetector CT angiography findings in a child with complete agenesis of the corpus callosum associated with a colloid cyst and trifurcation of the anterior cerebral artery. Although rare, a colloid cyst should be considered in the differential diagnosis of midline lesions in children with agenesis of the corpus callosum since it may require surgical intervention.