29-year-old male with cerebral cyst status post fenestration 3/30 with reservoir placement, prior hemorrhage. History of pleomorphic xanthoastrocytoma, status post laser ablation. Susceptibility from the patient's ventricular drain reservoir induces artifact. Given this caveat:Redemonstrated is a partially cystic, partially solid tumor centered on the tectum. The overall size of the lesion, inclusive of both cystic and solid components, measures 35 x 37 mm transaxial by 43 mm craniocaudal, previously 35 x 37 mm transaxial by 48 mm craniocaudal (as measured on the most recent noncontrast head CT 4/8/2015), demonstrating a decrease in its craniocaudal dimension. This lesion continues to exert mass effect with deformation of adjacent structures. A cystic component of the lesion extends into and deforms the right cerebral peduncle to a similar degree as identified on the recent CT. As before, the cerebral aqueduct is displaced to the left and narrowed, and the cerebellar vermis is displaced posteriorly. The primarily more posteromedially located enhancing portion of the mass measures 18 x 18 mm in transaxial dimension, demonstrating some enlargement when compared to the most recent contrast enhanced MRI exam of 3/31/2015 were it measured 18 x 16 mm when measured at the same location.Previously identified hemorrhage within the right frontal lobe appears to have resolved, although portions of this previously identified hemorrhage are obscured on some sequences by the aforementioned artifact.Stable position of two frontal ventriculostomy catheters. The more anterior ventriculostomy catheter tip terminates in the anterior horn of right lateral ventricle. The tip of the most posterior ventriculostomy catheter terminates within the cystic components of the posterior fossa mass.The size of the ventricular system has not significantly changed compared to the prior exam. Stable mild encephalomalacia in the right parieto-occipital region. No new parenchymal lesions are identified. The paranasal sinuses and mastoid air cells are clear. Expected vascular flow-voids are demonstrated.
Since the prior examination, the overall cystic and solid tectal region lesion has decreased in its craniocaudal dimension when compared to the most recent noncontrast head CT dated 4/8/2015. The primarily more posteromedially located enhancing portion of the mass demonstrates some enlargement when compared to the most recent contrast enhanced MRI exam of 3/31/2015.