A WHO grade IV malignant astrocytic tumor that arises from the brain, usually the cerebral hemispheres. It is characterized by the presence of poorly differentiated astrocytes, cellular polymorphism, nuclear atypia, and increased mitotic activity. The prognosis is poor. The disease is Monarch Disease Ontology identifier MONDO_0002501 (brain glioblastoma). Also known as: brain glioblastoma (disease), brain glioblastoma multiforme, brain glioblastoma multiforme (disease), glioblastoma multiforme of brain, glioblastoma multiforme of the brain, grade IV astrocytic tumour of brain, grade IV brain astrocytic tumour.