History of epidermoid cyst status-post CyberKnife treatment needs surveillance scan. Redemonstrated are postoperative findings related to left temporal craniotomy. There is a lobulated non-enhancing T2 hyperintense mass that displays restricted diffusion centered within the left choroid fissure with extension into the suprasellar cistern and third ventricle, as well as a separate punctate focus in the right occipital horn. The lesion appears to be unchanged in size, the main component of which measures 41 AP x 34 RL x 29 SI mm. However, there is interval increase in the T2 hyperintensity in the adjacent brain parenchyma. Additionally, the parenchyma along the posterolateral margin of the cyst now enhances, suggestive of radiation necrosis. There is unchanged regional mass effect upon the brain parenchyma and left aspect of the optic apparatus. There is a right transoccipital ventricular shunt catheter that terminates in the right lateral ventricle, which is unchanged. There is no evidence of intracranial hemorrhage or acute territorial infarct. There is no midline shift or herniation. The skull and scalp soft tissues are unchanged.
1.Stable size of the epidermoid cyst centered in the left choroid fissure with associated presumed treatment effects in the adjacent brain parenchyma.2.The shunted ventricular system is unchanged in size, with a possible fragment of epidermoid in the right occipital horn.