There is surrounding hyperintensity respresenting edema and possibly non-enhancing tumor extension. Glioblastoma Multiforme is the most common and most malignant primary intracranial tumor. It is a type of astrocytoma. Necrosis is the hallmark. Hemorrhage, edema and mass effect are common.
Histologic appearance is highly variable.
Usually located in deep cerebral white matter, especially frontal and temporal lobes. They commonly cross the corpus callosum. CNS extension is common including satellite lesions, ependymal and pial extension and subarachnoid and CSF seeding. Marked low density from edema with an inhomogeneous mass, which may be barely visible. Calcification is uncommon, and when present is thought to be related to a pre-existing low grade astrocytoma.