How Do I Know If I Have a Brain Tumor?

  • Medical Reviewer: Dany Paul Baby, MD
Medically Reviewed on 6/22/2022

What are the causes of brain tumors?

A brain tumor is a condition that leads to the growth of abnormal cells in your brain. Signs of a brain tumor include personality changes, vision changes, numbness and other symptoms.
A brain tumor is a condition that leads to the growth of abnormal cells in your brain. Signs of a brain tumor include personality changes, vision changes, numbness and other symptoms.

A brain tumor is a condition that leads to the growth of abnormal cells in your brain. Brain tumors can either be malignant (cancerous) or benign (noncancerous). We look at some of the causes and common symptoms of brain tumors and possible treatments for this condition.

Tumors that first appear in your brain are called primary tumors. Sometimes, cancer can spread from other parts of your body to your brain. These are called metastatic or secondary tumors.

The causes of brain tumors depend on the type and where they began. Primary brain tumors may begin in:

  • The brain
  • Tissues close to the brain 
  • Membranes that cover the brain
  • The cranial nerves
  • The pituitary gland
  • The pineal gland

A primary brain tumor occurs when DNA in normal brain cells starts mutating causing the cells to multiply quicker than they would normally. These cells continue to thrive while normal cells die and lead to a collection of abnormal cells that are called a tumor.

What are the signs of brain tumors?

The symptoms of a brain tumor depend on the type, size, and location of the tumor in the brain. Some of the signs of tumors in specific regions of your brain are listed below.

Frontal lobe

Symptoms include changes in personality, increased aggression, unusual gait, and an inability to execute speech.

Parietal lobe

Symptoms include an inability to understand speech, loss of senses, and problems with reading and writing.

Temporal lobe

Symptoms usually include seizures commonly linked to unusual smells, forgetfulness, especially when it comes to words, and short-term memory loss.

Occipital lobe

A tumor in the occipital lobe typically leads to issues with your vision.


Some of the symptoms are difficulties in coordinating your movements, spontaneous eye movement, stiffness in the neck, and nausea and dizziness.

Brain stem

Symptoms include issues with swallowing, droopy eyelids or mouth (typically on one side of your face), issues with speech, and double vision.

Spinal cord

Symptoms include weakness in your hands and legs, numbness, and an inability to control your bladder or bowel.

Pituitary gland

Symptoms include mood swings, high blood pressure, diabetes, enlarged hands and feet, and infertility. Women with this condition may also have irregular periods.

How to diagnose brain tumors?

Brain tumors are generally detected only after the onset of symptoms. Your doctor can use several tests to diagnose and understand the type of brain tumor. These tests will help your doctor determine the best treatments for your condition.

The tests are decided based on your symptoms, age, general health condition, and medical history.

Magnetic Resonance Imaging (MRI)

An MRI uses magnetic fields to get images of the body and helps determine the size of the tumor. There are different types of MRI scans and these are preferred to CT scans due to the clarity that they offer.

  • Contrast MRI scans typically use gadolinium (a chemical used to highlight abnormal tissues). The image produced by this scan is compared to another one you get after doing a regular MRI scan to detect the contrast and the abnormal tissues that gadolinium has highlighted.
  • Magnetic resonance spectroscopy (MRS) helps doctors identify the cancerous cells in your brain. This helps doctors understand the chemical makeup of your brain after radiation therapy.
  • Doctors can also use two separate techniques called “diffusion-weighted imaging” (to highlight the cellular structure of the tumor) and “perfusion imaging” (to show how much blood the tumor gets). This gives them an idea of the effectiveness of the treatments.
  • A functional MRI (fMRI) is usually done when the tumor needs surgery. In this procedure, you’ll be asked to do some mental tasks such as thinking about certain topics that will cause small blood flow changes in your brain. This will be highlighted in the fMRI image. It gives doctors critical information about which parts of your brain are active to avoid any damage to these parts during surgery.
  • A spinal MRI can help detect the tumor on or around your spine.

Tissue sampling or biopsy

MRIs determine the presence of a tumor. Once this is confirmed, doctors usually do a biopsy on a tissue sample to identify the type of tumor.

A biopsy involves removing a small part of the tissue from the affected area of the brain and studying it under a microscope. It’s the only conclusive way to know if there’s a tumor.

A biopsy can be done as part of surgery to remove the tumor. In some cases, removing the tumor may not be possible to avoid other complications.

A pathologist examines this sample and does some tests to determine the presence of a tumor. A pathologist is also a doctor who specializes in testing and assessing different organs to arrive at a diagnosis.

Your doctor may also do some of these tests to know whether the treatment is working.

Positron emission tomography (PET)

A PET scan is combined with a CT scan to understand the effectiveness of the treatment. This involves injecting a small amount of radioactive substance into your body. Tumor cells are known to take up radioactive substances and this is how cancerous cells are detected.

A specialist will use a scanner to detect the radioactive substance in the cells. The amount of radioactive substance is too low to cause any harm.

Biomarker testing

Also called molecular testing of the tumor, this involves running some tests on the tissue sample to locate specific genes, proteins, and other factors that are specific to the tumor.

The presence or absence of specific molecules in the tumor gives doctors essential information about the possible treatment options and the chances of recovery.

Neurological tests

These tests help doctors determine whether the tumor affects normal brain functions such as vision and hearing.


Which of these is NOT a type of head and neck cancer? See Answer

When should you see a doctor?

The symptoms and signs given here could overlap with other conditions. If you have any of these symptoms, schedule an appointment with your doctor to get the right diagnosis.

An early diagnosis is important as it gives the doctors enough time to understand the cause of your symptoms and decide on the correct treatment for your condition.

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Medically Reviewed on 6/22/2022

Johns Hopkins Medicine: "Brain Tumors and Brain Cancer."

Mayo Clinic: "Brain tumor."

Moffitt Cancer Center: "Brain Tumor Diagnosis - MRI."

Radiology Info: "Brain Tumors."