Contrast enhanced CT of a juvenile pilocytic astrocytoma (JPA). Notice that there is a characteristic "cyst and mural nodule" morphology. The key feature here is that most of the cyst lining does NOT show contrast enhancement. Notice that this nodule has a central area without enhancement - due to a cyst within the nodule (NOT necrosis). Although the appearance can be variable, both JPA and hemangioblastoma can be suggested when a cerebellar lesion has a "cyst and nodule" appearance.