Core Terms & Classification
Brain tumor
A brain tumor is an abnormal growth of cells in or around the brain, which may be benign or malignant and may begin in the brain or spread from elsewhere.
In short: Brain tumor
- It is an abnormal growth of cells in or around the brain.
- It can be benign (non-cancerous) or malignant (cancerous).
- It can be primary (starting in the brain) or metastatic (spread from elsewhere).
- Gliomas are one major category of primary brain tumor.
What it is
A brain tumor is an abnormal growth of cells in or around the brain. Brain tumors are a diverse group: they can be benign or malignant, can begin in the brain (primary) or spread to it from cancer elsewhere in the body (metastatic), and can arise from many different cell types.
Understanding Brain tumor
Because the brain contains many cell types, brain tumors are highly varied. They are broadly divided into primary brain tumors (which begin in the brain or its coverings) and metastatic tumors (which spread from cancers elsewhere, such as lung or breast cancer). Primary brain tumors include gliomas (from glial cells), meningiomas (from the brain's coverings), and others. Even within "brain tumor," behavior ranges from slow-growing and curable to rapidly progressive. The specific type, grade, location, and (for gliomas) molecular features determine the diagnosis and treatment. Glioma is one important category of primary brain tumor, and the focus of this library. Understanding the broad landscape of brain tumors helps place glioma in context.
Why it matters
Understanding the broad category of brain tumors helps patients and families place a glioma diagnosis in context — distinguishing primary from metastatic tumors and recognizing that "brain tumor" covers a wide range of conditions.
Common questions
What is a brain tumor?
An abnormal growth of cells in or around the brain.
Can brain tumors be benign?
Yes — they can be benign or malignant.
Where does glioma fit?
Glioma is one major category of primary brain tumor.
Bottom line
A brain tumor is an abnormal growth in or around the brain, which may be benign or malignant and primary or metastatic; glioma is a major primary type.
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