Types of Brain and Spinal Cord Tumors
Brain and spinal cord tumors are named based on where they begin, and the main cell type they contain. Glial cells make up 90% of our brain cells, and they play a major role in how we think. There are many types of glial cells.
The World Health Organization (WHO) classifies brain tumors by their cell type, location, how they behave, and their molecular features. Some tumors are also given a grade based on how fast they grow and spread. Grades range from “grade I” (benign or the least aggressive), to “grade IV” (malignant and the most aggressive). Tumors graded in the I-II range are usually easier to treat and manage.
These tumors begin in brain cells called astrocytes (a type of glial cell), which help keep nerve cells healthy.
- Brain Stem Glioma Pilocytic Astrocytoma (grade I)
- Diffuse Astrocytoma (grade II)
- Anaplastic Astrocytoma (grade III)
- Glioblastoma (grade IV)
Astrocytomas are divided into two categories: those with and without isocitrate dehydrogenase (IDH) mutations. IDH mutations are more common and tend to grow more slowly.
These tumors begin in brain glial cells called oligodendrocytes.
- Oligodendroglioma (grade II)
- Anaplastic oligodendroglioma (grade III)
Oligodendrogliomas with IDH mutations tend to grow more slowly.
These tumors have both oligodendrocytes and astrocytes—and often start in in the cerebrum. With modern molecular testing (IDH mutations and 1p/19 codeletion), most of these tumors are found to be one type or the other. True oligoastrocytomas are very rare.
- Oligoastrocytoma (grade II)
- Anaplastic oligoastrocytoma (grade III)
These tumors begin in cells that line the fluid-filled spaces of the brain and spinal cord called the ependyma. Ependymal cells are a type of glial cell and ependymomas are considered a type of glioma.
- Ependymoma (grade I or II)
- Anaplastic ependymoma (grade III)
Pineal Parenchymal Tumors
These tumors form in the cells that make up most of the pineal gland (the gland that makes melatonin). These tumors are different from pineal astrocytic tumors.
- Pineocytomas (grade II)
- Pineoblastomas (grade IV)
This tumor forms in the meninges (thin layers of tissue that cover the brain and spinal cord). It can form from different types of brain or spinal cord cells. Most meningiomas are slow growing grade I tumors. Grade II and III meningiomas are more aggressive.
- A hemangiopericytoma/solitary fibrous tumor resemble meningiomas but are different biologically and treated like a grade II or III meningioma
Germ cell tumors usually form in the center of the brain, near the pineal gland. They can spread to other parts of the brain and spinal cord. These tumors impact the cells that develop into sperm in men or ova (eggs) in women. They can be either benign or malignant. Types include:
- Embryonal yolk sac carcinomas
This tumor begins in the center of the brain, just above the back of the nose. It can form from different types of brain or spinal cord cells.
- Pituitary Tumors
- Craniopharyngioma (grade I)
Signs & Symptoms
Symptoms are closely related to where the tumor forms and how it affects that part of the brain.
The brain has three main sections:
Cerebrum - The largest part of the brain, at the top of the head. It controls thinking, learning, problem solving, emotions, reading, writing, and voluntary movement. In many people, the left side of the brain controls speech.
Cerebellum - The lower back of the brain, near the middle of the back of the head. It controls movement, balance, and posture.
Brain Stem - The lowest part of the brain (just above the back of the neck). The brain stem connects the brain to the spinal cord. It controls breathing, heart rate, and the nerves and muscles used in seeing, hearing, walking, talking, and eating.
The spinal cord connects the brain to nerves in most parts of the body. Spinal cord nerves carry messages between the brain and the rest of the body.
Most Common Signs of a Brain or Spinal Cord Tumor
- Morning headache or headache that goes away when standing
- Frequent nausea and vomiting
- Vision, hearing, and speech problems
- Loss of balance and trouble walking
- Weakness on one side of the body
- Numbness on one side of the body
- Unusual sleepiness or change in activity level
- Unusual changes in personality or behavior
- Trouble with thinking and memory
Spinal Cord Tumors
- Back pain or pain that spreads from the back towards the arms or legs
- A change in bowel habits or trouble urinating
- Weakness in the legs
- Numbness in the legs or trunk
- Trouble walking