Brain tumors can develop anywhere in the brain, but certain locations are more common than others. The most frequent sites for brain tumors differ based on whether the tumor is cancerous (malignant) or non-cancerous (benign).
Most common locations for cancerous brain tumors
The most common locations for malignant brain tumors include:
- Frontal lobe – The frontal lobe is located at the front of the brain and is involved in personality, cognition, and movement. It is the site of about 18% of malignant brain tumors.
- Temporal lobe – The temporal lobes are located on the sides of the brain and are involved in memory, speech, and hearing. About 16% of cancerous brain tumors develop here.
- Parietal lobe – The parietal lobe is located at the top back area of the brain. It plays a role in processing touch, temperature, and pain sensations. Around 13% of malignant brain tumors occur in the parietal lobe.
- Occipital lobe – The occipital lobe is located at the back of the brain and processes visual information. It accounts for about 10% of cancerous brain tumors.
- Cerebellum – The cerebellum sits at the base of the brain and controls coordination and balance. It represents the site of around 10% of malignant brain tumors.
- Brain stem – The brain stem connects the brain to the spinal cord and controls vital functions like breathing and heart rate. About 10% of malignant tumors develop in the brain stem.
- Meninges – The meninges are the membranes that cover the brain. About 9% of cancerous brain tumors arise from the meninges.
- Pituitary gland – The pituitary gland sits at the base of the brain and produces hormones. It develops a cancerous tumor in about 6% of brain tumor cases.
- Ventricles – The ventricles are fluid-filled cavities within the brain. Malignant brain tumors can sometimes arise from the cells lining the ventricles.
Most common locations for benign brain tumors
The most frequent sites for non-cancerous brain tumors include:
- Cerebellum – Up to 40% of benign brain tumors develop in the cerebellum.
- Pituitary gland – About 25% of non-cancerous brain tumors affect the pituitary gland.
- Meninges – Around 20% of benign tumors arise from the meninges.
- Cranial nerves – Cranial nerves control processes like vision, eye movement, hearing, and swallowing. About 8% of benign tumors occur on cranial nerves.
- Pineal gland – The pineal gland produces melatonin and regulates sleep cycles. Around 5% of non-malignant brain tumors develop here.
Brain tumor location by age
The most common sites for brain tumors can vary based on a person’s age:
| Age Group | Most common brain tumor locations |
|---|---|
| Children (under 15) |
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| Adolescents and young adults (15-39) |
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| Middle-aged adults (40-64) |
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| Older adults (over 65) |
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In children, many brain tumors develop in the cerebellum and brain stem. In adolescents and young adults, tumors often arise in sites like the cerebrum and pituitary gland. For middle-aged and older adults, the cerebrum and meninges are the most common locations.
Brain tumor location and cell origins
The types of cells that a brain tumor originates from can also influence its location in the brain. Some patterns include:
- Glial cell tumors – Glial cells provide support and insulation for neurons. Tumors developing from glial cells (gliomas) represent about 30% of brain tumors and often occur in the cerebrum.
- Meningiomas – These tumors arise from the meninges and develop in areas like the convexity of the brain and skull base.
- Pituitary adenomas – These benign tumors affect the pituitary gland at the base of the brain.
- Medulloblastomas – These embryonic tumors grow in the cerebellum and tend to affect children.
- Schwannomas – Schwann cells produce myelin insulation around peripheral nerves. Schwannomas are benign tumors that can develop on cranial nerves.
- Craniopharyngiomas – These rare, non-cancerous tumors emerge near the pituitary gland, near the hypothalamus.
Factors influencing brain tumor location
Researchers are still investigating why brain tumors tend to develop in certain areas. Some contributing factors may include:
- Cell density – Areas with more actively dividing cells, like the cerebrum, may have increased risk.
- Hormones – Hormonal influences on cell growth may contribute to tumors in sites like the pituitary.
- Brain development – Embryonic cell types in some brain regions may be more tumor-prone.
- Toxins or radiation – Environmental exposures could promote tumors in exposed areas.
- Head injuries – Some data link head trauma to increased risk in sites like the meninges.
- Genetic mutations – Inherited conditions tied to tumors often affect specific brain regions.
Brain tumor classification systems
In addition to location, brain tumors are classified based on cell origin and how quickly they grow:
- WHO grading system – The World Health Organization (WHO) assigns tumor grades from I to IV based on how aggressively they grow and spread. Grade I is least aggressive and grade IV is most aggressive.
- Benign vs. malignant – Benign tumors have distinct borders, grow slowly, and rarely spread. Malignant tumors tend to have blurred edges, grow rapidly, and can invade other areas.
- Primary vs. secondary – Primary brain tumors start in the brain. Secondary tumors spread from cancers elsewhere in the body to the brain.
Common types of primary brain tumors
| Tumor Type | WHO Grade | Location |
|---|---|---|
| Meningioma | Most are grade I | Meninges |
| Glioblastoma | Grade IV | Cerebrum |
| Astrocytoma | Grade II-IV | Cerebrum, brain stem |
| Oligodendroglioma | Grade II-III | Cerebrum |
| Medulloblastoma | Grade IV | Cerebellum |
| Ependymoma | Grade II-III | Brain stem, ventricles |
| Schwannoma | Grade I | Cranial nerves |
| Pituitary adenoma | Usually grade I | Pituitary gland |
Conclusion
In summary, the frontal and temporal lobes of the cerebrum are the most common sites for malignant brain tumor development. For benign tumors, the cerebellum and pituitary gland are most frequently affected. A tumor’s location often provides clues about its cell origin and biological behavior. Understanding where brain tumors occur and why may help guide future preventive and therapeutic efforts against these diseases.