Types of brain tumors
There are different types of brain tumors and these different kinds behave differently; tumors can be benign (non-cancerous) or malignant (cancerous). Brain tumors are often classified based on the area where the cancer cells start to develop.
More than half of all primary brain tumors are gliomas. These tumors develop from the main support cells in the brain called glial cells.
Astrocytomas are the most common type of glioma. It develops from cells called astrocytes. There are three types:
- astrocytoma – these are low-grade gliomas (grade 1 or 2)
- anaplastic astrocytoma – these are grade-3 gliomas
- glioblastoma or glioblastoma multiforme (GBM) – these are grade-4 gliomas
Oligodendrogliomas start in the cells of the oligodendrocytes. These are cells that cover the nerve cells. Oligodendrogliomas can be slow-growing (grade 2) or can grow more rapidly (grade 3)
- Mixed gliomas
Mixed gliomas are made up of more than one type of cell. For example, oligo-astrocytomas are a mixture of astrocytes and oligodendrocytes.
Ependymomas are a rare type of glioma starting in the cells that cover the fluid-filled spaces in the brain (ventricles) and the spinal cord. They are generally slow-growing.
Meningiomas start in the meningioma, which are tissues that cover and protect the brain and spinal cord. They are usually benign tumors that grow very slowly. Sometimes, meningiomas are malignant. This is a common type of brain tumor.
Central nervous system lymphoma
A lymphoma is a malignant tumor of the lymphatic system. The lymphatic system help the body defend itself against infection and disease. Lymphomas that start in the brain are called primary central nervous system lymphomas and are rare. People who have weakened immune systems are at a greater risk of developing this type of tumor.
These are benign tumors that start in the nerve that controls hearing and balance, called the acoustic nerve. This nerve is covered by cells called Schwann cells, which is why this tumor is also known as a schwannoma. People who have a genetic condition called neurofibromatosis type 2 (NF2) are at a greater risk of developing this type of tumor.
This is a rare type of tumor that develops from the cells that cover the blood vessels in the brain. Hemangioblastomas are benign and grow slowly.
Pituitary tumors are also known as pituitary adenomas and are benign.
Different types of tumors can start in the spinal cord; these include astrocytomas, meningiomas, spinal schwannomas, ependymomas, and hemangioblastomas. These are generally benign.
The pineal gland is located just below the area where the two hemispheres of the brain join together. The tumors in this part of the brain are rare and may contain different types of cells. They may be slow- or fast-growing. The most common type are germinomas, though others include teratomas, pineocytomas, and pineoblastomas.
These occur rarely in adults, though they are one of the most common malignant tumors of the brain in children. This tumor develops from cells that remain from the first stages of development. It is a type of primitive neuroectodermal tumor (PNET).