Glioblastoma multiforme, also known as grade 4 astrocytoma is the most common and aggressive type of primary brain tumor, accounting for 52 percent of all primary brain tumors cases.

Treatment can involve chemotherapy, radiotherapy and surgery. The 5 year survival rate of the disease has remained unchanged over the past 30 years, and stands at less than three percent. Even with complete resection of the tumor, combined with the best available treatment, less than 25 percent survive more than 5 years. Chromosomal aberrations like PTEN mutation, MDM2 mutation, and p53 mutation are commonly seen in these tumors. Growth factor aberrant signaling associated with EGFR , and PDGF are also seen. Tumors of this type have a tendency to infiltrate across the corpus callosum, producing a butterfly glioma.

Glioblastoma multiformes are characterized by the presence of small areas of necrotizing tissue that is surrounded by highly anaplastic cells. This characteristic differentiates the tumor from Grade 3 astrocytomas . Although glioblastoma multiforme can be formed from lower grade astrocytomas , post-mortem autopsies have revealed that most glioblastoma multiforme are not caused by previous lesions in the brain. Metastasis of the tumor beyond the Central Nervous System is extremely rare.

Common symptoms of the disease include seizure, headache, hemiparesis, and personality change. Unlike oligodendrogliomas , glioblastoma multiformes can form in either the gray matter or white matter of the brain.