Right frontal craniotomy. A large cystic space that follows CSF signal on all sequences demonstrates similar dimensions when compared to the previous CT brain, although has distinctly enlarged when compared to the more distant CT brain from years ago. This lesion demonstrates a gently lobulated margin with some thin non-enhancing septations noted superiorly. A small volume of non-enhancing material lies dependently within. Inferiorly, this cystic lesion appears to abut white matter of the deep right frontal lobe with no intervening cortex. There is no associated enhancing components to this cystic structure. No communication with the right lateral ventricle. Increased size results in a progressive mass effect, with partial effacement of the right lateral ventricle as well as subfalcine herniation and mild right uncal herniation. No evidence of entrapment of the left lateral ventricle. Remote from this cystic lesion, the remainder of the intracranial structures have a normal appearance. The optic nerve sheaths are noted to be symmetrically mildly CSF distended.