Glioblastoma is a complex type of cancerous tumor that forms in the tissue of the brain or spinal cord. Glioblastomas can occur in any lobe of the brain, but they are most often found in the temporal and frontal lobe. These types of tumors occur more often in adults, and more often in the brain than the spinal cord.

Gliomas are brain tumors that come in grades II, III, and IV (IV is the most malignant). Glioblastomas are considered to be grade IV tumors. They do not spread (or metastasize) to other parts of the body, but they can metastasize to other parts of the brain very quickly.