Brain and spinal cord tumors are named based on the type of cells that make them up and where in the brain in the central nervous system (CNS) they first arise. An astrocytic tumor begins in star-shaped brain cells called astrocytes. These cells help nerve cells stay healthy. This is the case of anaplastic astrocytoma, diffuse astrocytoma, and brain stem glioma. An oligodendroglial tumor begins in brain cells called oligodendrocytes, which help keep nerve cells healthy.
There are also ependymal tumors, which usually begin in the cells that line the fluid-filled spaces of the brain and those that surround the spinal cord. To these are added meningeal tumors or meningiomas , which form in the thin layers of tissue that cover the brain and spinal cord. And medulloblastomas , embryonal tumors that form in the fetus and can spread from the brain to the spine through cerebrospinal fluid (CSF). As for craniopharyngioma, it is a rare tumor that usually forms just above the pituitary or pituitary gland.
Tumor grade (I, II, III, and IV) can be used to tell the difference between slow-growing and fast-growing tumors . The grade of the tumor is based on how abnormal the cells look under a microscope and how quickly the tumor is likely to grow and spread.
Primary tumors can be benign or cancerous. In adults, the most common types of brain tumors are gliomas and meningiomas . Gliomas are tumors that develop from glial cells, which normally support the structure of the central nervous system, provide nutrition to the central nervous system, remove cellular debris, and break down dead neurons. Gliomas can develop from different types of glial cells, which can be: astrocytic tumors such as astrocytomas, which originate in the brain; Oligodendroglial tumors, which are often found in the frontal temporal lobes, and glioblastomas, which originate in supporting brain tissue and are the most aggressive type.
Other primary brain tumors include: pituitary tumors, which are usually benign; pineal gland tumors, which can be benign or malignant; ependymomas, which are usually benign; Craniopharyngiomas, which appear mainly in children and are benign, but can have clinical symptoms such as vision changes and premature puberty; Primary central nervous system (CNS) lymphomas, which are malignant; primary germ cell tumors of the brain, which can be benign or malignant; meningiomas, which originate in the meninges schwannomas, which arise in cells that make the protective covering of nerves (myelin sheath) called Schwann cells.
Unlike cancers that start in other parts of the body, tumors that start in the brain or spinal cord rarely spread to distant organs. Still, brain or spinal cord tumors are rarely considered benign (not cancerous).
