An astrocytic tumor begins in the brain cells called astrocytes, a star-shaped type of glial cell that keeps nerve cells healthy. The astrocytic glioma, as it’s called, is the most common tumor affecting the primary central nervous system (i.e., the brain and spinal cord). These tumors comprise two thirds of all tumors involving glial cells. There are several different types of astrocytic tumor, including:
- Brain stem glioma: This type of brain tumor forms in the brain stem, the part of the brain that connects to the spinal cord. This is often considered a high-grade tumor that spreads quickly throughout the brain stem and is difficult to cure. It rarely occurs in adults.
- Pineal astrocytic tumor: This type of tumor forms around the pineal gland, a tiny organ in the brain that makes melatonin, a hormone involved in the sleep cycle. These tumors can be of any grade.
- Pilocytic astrocytoma (grade I): This tumor grows slowly in the brain or spinal cord, and may be in the form of a cyst. It rarely spreads into adjacent tissues or causes death. This tumor is most commonly found in children and young adults with neurofibromatosis type 1.
- Diffuse astrocytoma (grade II): These slow-growing tumors often spread into nearby tissue, and can sometime progress into a higher-grade tumor and become an anaplastic astrocytoma or glioblastoma. They most often form in the cerebrum, but can form in any part of the brain; they’re most commonly found in young adults and people with Li-Fraumeni syndrome, a rare genetic condition that predisposes patients to cancer.
- Anaplastic astrocytoma (grade III): This type of brain tumor grows quickly and spreads into nearby tissue. It most often forms in the cerebrum and is most commonly found in adults. This tumor can progress into a glioblastoma.
- Glioblastoma (grade IV): This type of tumor usually forms in the cerebrum and spreads very quickly. Most common in adults, it has a poor prognosis.