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Brain tumor

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A brain tumor is a mass of cells that grow out of control within the brain. This abnormal growth occurs when cells do not stop dividing like they should. These masses are sometimes called brain cancer. Scientists classify tumors into two main categories: benign and malignant. Benign tumors are non-cancerous and usually grow in only one area. Malignant tumors are cancerous and can be much more dangerous.

Brain headBorder
Brain headBorder

Tumors are also categorized by where they first appear. Primary tumors originate directly within the brain tissue. Secondary tumors, also known as brain metastasis, start elsewhere in the body and spread to the brain. In fact, secondary tumors are about four times as common as primary ones. About half of these metastatic tumors come from lung cancer. Globally, primary brain tumors affect roughly 250,000 people every year.

Meninges diagram
Meninges diagram

The brain is protected by a three-layered covering called the meninges. These layers include the dura mater, the arachnoid mater, and the pia mater. The arachnoid and pia layers are often called the leptomeninges. Between these layers is the subarachnoid space, which contains cerebrospinal fluid. This fluid supports and protects the brain tissue. Tumors that grow in these protective membranes are called meningiomas. While these are often benign, they can still be life-threatening depending on their size and location.

Meningioma of the sagittal sinus isolated
Meningioma of the sagittal sinus isolated

Inside the brain, cells are divided into two main types: neurons and glia. Neurons carry signals, while glial cells provide structural and metabolic support. Primary tumors that grow from glial cells are called gliomas. These are often malignant by the time doctors find them. The brain is divided into specific regions called lobes, each with a unique job. A tumor's impact depends heavily on which part of the brain it touches.

Postermass
Postermass

Symptoms change based on the tumor's location and size. A tumor in the frontal lobe might cause personality changes or poor reasoning. If a tumor is in the temporal lobe, it may affect memory or language comprehension in Wernicke's area. The occipital lobe manages vision, so damage there can cause sight loss. The cerebellum controls balance and muscle movement. Tumors in the brainstem can cause seizures, breathing changes, or even partial paralysis.

Tumor BrainstemGlioma2
Tumor BrainstemGlioma2

Diagnosing a brain tumor is a complex process. Doctors use medical exams to rule out infections first. They then use imaging tools like computed tomography (CT) or magnetic resonance imaging (MRI). These scans are vital because they can show if the blood-brain barrier has been disrupted. The blood-brain barrier is a membrane that protects the brain from toxins. Many tracers used in medical imaging cannot reach the brain unless the tumor disrupts this barrier. Doctors often confirm their findings with a biopsy, which involves taking a small tissue sample.

CT brain tumor
CT brain tumor

While the cause of most tumors is unknown, some risk factors exist. Ionizing radiation is a known cause, and up to 4% of brain cancers may stem from CT scan radiation. Some people have inherited syndromes, such as neurofibromatosis or von Hippel-Lindau disease, that increase their risk. In children under age 15, brain tumors are the second most common cancer, following acute lymphoblastic leukemia. Treatment plans often combine surgery, radiation therapy, and chemotherapy. Doctors may also use dexamethasone or furosemide to reduce swelling around the tumor.

Oligodendroglioma1 high mag
Oligodendroglioma1 high mag
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🖼️ Images & Media (7)
File:Brain headBorder.jpg
Brain headBorder.jpg
File:Meninges diagram.jpg
Meninges diagram.jpg
File:Postermass.png
Postermass.png
File:CT brain tumor.jpg
CT brain tumor.jpg
File:Oligodendroglioma1 high mag.jpg
Oligodendroglioma1 high mag.jpg
File:Meningioma of the sagittal sinus isolated.jpg
Meningioma of the sagittal sinus isolated.jpg
File:Tumor BrainstemGlioma2.JPG
Tumor BrainstemGlioma2.JPG
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