Male, 28 years old, history of pleomorphic xanthoastrocytoma status post laser ablation. Surveillance scan. A partially cystic, partially solid tumor is again seen centered on the tectum. Since the prior examination, the overall size of the lesion, inclusive of both cystic and solid components, has increased and now measures 40 x 34 mm transaxial by 46 mm craniocaudal, previously 35 x 27 mm transaxial by 35 mm craniocaudal (10/22/14 scan). This interval change in size represents primarily an increase in the cystic components of the lesion while the solid components have probably decreased in overall volume.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 greater degree than on prior exams. The midbrain and as a whole is deformed, the cerebral aqueduct is displaced to the left and narrowed, and the cerebellar vermis is displaced posteriorly.A right frontal approach ventricular catheter is in place, tip within the right frontal horn similar to prior. The lateral and third ventricles remain enlarged but without significant interval change from prior. The fourth ventricle is effaced. A linear tract of T2 hyperintensity running across the right occipital lobe is unchanged and compatible with prior instrumentation. No new intracranial lesions are seen.
Since the prior examination, the cystic and solid tectal region lesion has increased in overall size. This represents primarily an increase in the size and volume of the cystic components, as the solid components seem to have decreased mildly.