Colloid Cyst Hydrocephalus

This is a case of colloid cyst of the third ventricle complicated by severe hydrocephalus, raised intracranial pressure and papilledema. Figure 1: Fundus photographs demonstrating bilateral optic nerve head edema Figure 2a and 2b: T1-weighted axial brain MRI without contrast: Dilation of both lateral ventricles (yellow arrows) suggesting hydrocephalus Figure 3: T1-weighted brain MRI without contrast : There is a T1 isointense lesion within the third ventricle (yellow circle) Figure 4 : T1-weighted sagittal brain MRI showing several radiologic signs of raised intracranial pressure Figure 4a: Dilation of the lateral ventricles with normal sized (or even small) fourth ventricle (yellow arrow), suggesting an obstruction at the level of the third ventricle (foramen of Monro) Figure 4b: Displacement of the cerebellar tonsils (arrow) below the foramen magnum (dashed yellow line) Figure 4c: The sella has a shallow shape (yellow arrows), and the pituitary appears flat (blue arrow) consistent with a partially empty sella.