Brain Lesions: Causes, Symptoms, Treatments

Medically Reviewed by Christopher Melinosky, MD on September 11, 2022

When you scrape your elbow, it leaves an area of inflamed skin, or a lesion. But what are lesions in the brain? And what causes them? How serious are brain lesions and how are they treated? Here is information about this confusing and unsettling health concern.

What Are Brain Lesions?

A lesion is an area of tissue that has been damaged through injury or disease. So a brain lesion is an area of injury or disease within the brain. While the definition sounds simple, understanding brain lesions can be complicated. That's because there are many types of brain lesions. They can range from small to large, from few to many, from relatively harmless to life threatening.

What Causes Brain Lesions?

Brain lesions can be caused by injury, infection, exposure to certain chemicals, problems with the immune system, and more. Typically, their cause is unknown.

What Are the Symptoms of a Brain Lesion?

Symptoms of a brain lesion vary depending on the type, location, and size of the lesion. Symptoms common to several types of brain lesions include the following:

What Are the Different Types of Brain Lesions?

Although they share a common definition -- injury or damage to tissue within the brain -- brain lesions vary greatly. Here are some common brain lesions.

Abscesses: Brain abscesses are areas of infection, including pus and inflamed tissue. They are not common, but they are life threatening. Brain abscesses often occur after an infection, usually in a nearby area, such as an ear, sinus, or dental infection. They can also appear after injury or surgery to the skull. Read more about the causes of abscesses.

Arteriovenous malformations (AVMs): An AVM is a type of brain lesion that occurs during early development. Arteries and veins in the brain grow in a tangle and become connected by tube-like structures called fistulae. The arteries are not as strong as normal arteries. The veins are often enlarge because of the constant flow of blood directly from the arteries through the fistulae to the veins. These fragile vessels may rupture, leaking blood into the brain. In addition, the brain tissue may not receive enough blood to function properly. Damage to the brain may cause seizures as the first symptoms of an AVM.

Cerebral infarction: Infarction refers to death of tissue. A cerebral infarction, or stroke, is a brain lesion in which a cluster of brain cells die when they don't get enough blood. Recognize the signs and symptoms of a stroke.

Cerebral palsy: This type of brain lesion occurs when a baby is still in the mother's womb, or during delivery. Cerebral palsy does not progress over time. The brain lesions affect the child's ability to move, which can also make communication and related skills difficult. However, many children with cerebral palsy have normal intellectual functioning. Read more on the symptoms and types of cerebral palsy.

Multiple sclerosis (MS): With this condition, the immune system attacks and damages the nerve linings (myelin) in the brain and spinal cord. These lesions make it difficult for messages to be sent and received properly between the brain and the rest of the body. Learn more about the symptoms of MS.

Tumors: Tumors are clumps of cells that grow abnormally from normal tissue. Some tumors in the brain are noncancerous, or benign. Others are cancerous. They may start in the brain, or they may spread from elsewhere in the body (metastatic). They may grow quickly or they may remain stable. Get more information on signs and symptoms of a brain tumor.

How Are Brain Lesions Diagnosed?

The methods used to find and diagnose brain lesions depend on the symptoms. In many cases, CT and MRI imaging studies help pinpoint the location, size, and characteristics of the lesions. Blood and other lab tests may also be done to look for signs of infection.

How Are Brain Lesions Treated?

Treatment depends on the type of brain lesion. The goals of treatment may be to provide a cure, relieve symptoms, or improve the quality or length of life. Common approaches for treating brain lesions include the following:

  • "Wait and see;" if the lesion is not causing problems and is not growing, you may only need periodic checkups.
  • Surgical removal of the lesion, if possible; new surgical techniques may make it possible to remove even hard-to-reach lesions.
  • Chemotherapy and radiation therapy for lesions that are cancerous
  • Medication to fight infections, such as antibiotics or other antimicrobial drugs
  • Medication to calm the immune system or otherwise change the immune system's response
  • Medication or other therapies to relieve symptoms associated with the brain lesion

How Can I Find Out More About Brain Lesions?

Brain lesions take many forms, so diagnosing and treating them can be complex. That's why it's important to discuss individual questions about brain lesions with your doctor. Together, you can determine the best way to proceed in identifying, treating, and living with brain lesions.

Show Sources


Merriam-Webster Medical Dictionary: "Abscess;" "Infarct;" "Lesion;" and "Tumor."

WebMD Medical Reference: "Alzheimer's Disease: The Basics."

eMedicineHealth: "Multiple Sclerosis (MS) FAQs;" "The Central Nervous System and Multiple Sclerosis--Causes;" "Brain Abscess;" "Alzheimer Disease;" "Arteriovenous Malformations;" "Stroke, Ischemic;" "Cerebral Palsy;" and "Brain Metastasis."

WebMD Medical Reference from Healthwise. "Adult Brain Tumors Treatment (PDQ®) - Classification)."

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