Brain tumor in dogs: causes, symptoms and treatment

Brain tumor is a disease that can be very serious in dogs. Causing pain and behavioral problems, it develops rapidly and the symptoms are unfortunately only visible when the tumor is already large. In the slightest doubt, it is advisable to act quickly. Let’s discover together the causes, symptoms and treatments of this pathology.

What is a brain tumor in dogs?

A tumor can develop in the brain of any living thing. It is an abnormal proliferation of cells that form a mass.

There are two types of tumours:

  • Primary tumours : these benign or malignant tumors form in brain cells and develop in the heart or on the periphery of the brain. The three most common forms in dogs are meningiomas, gliomas, and choroid plexus tumors.
  • Secondary tumours : these tumors are formed by a cluster of cells from another organ and then migrate to the brain where they metastasize. They come from a lymphoma, a hemangiosarcoma, a carcinoma or a pituitary tumour.


As its name suggests, a meningioma is a tumor that develops from the meninges, in other words the membrane surrounding the animal’s brain. It is mostly seen in older dogs, especially those with long muzzles. This type of tumor is more generally benign and easy to remove since it is located in the periphery of the brain, but it remains the most common form of primary tumor.


Glioma is due to the development of glial cells in the brain, those which ensure the protection of neurons and the central nervous system. This type of tumor develops on the contrary mainly in dogs with short muzzles and they are unfortunately systematically malignant. Difficult to operate, they are the second most common form of tumours.

Tumors of the choroid plexus

These tumors grow among the choroid plexuses, in charge of secreting the cerebrospinal fluid that envelops the brain and spinal cord. This tumor affects adult dogs and remains the rarest form of primary tumour.

What are the causes ?

It is not obvious to know the exact origin of the formation of a tumor in the dog. However, specialists agree on the fact that certain external factors can be the cause or at least favorable grounds:

  • food;
  • certain medications;
  • an accident or trauma;
  • exposure to a chemical or hazardous product;
  • a viral disease or an autoimmune disease.

Some breeds of dogs are more prone to developing tumors than others, for example the Labrador or the Golden Retriever. Typically, tumors develop in dogs between the ages of 8 and 12, but some can be affected as young as 5 years old.

What are the symptoms of a brain tumor in dogs?

A dog with a brain tumor shows some symptoms. However, it is not always easy to identify the disease when these occur. Indeed, as in humans, they are common to other pathologies and they vary according to the nature of the tumor and its location. Nevertheless, it is advisable to act very quickly in the case of a brain tumor in order to relieve the suffering of your dog with an adapted solution before the cancer is too widespread.

Watch it and watch out for the following symptoms:

  • seizures or convulsions;
  • signs of pain, in particular by a form of withdrawal, moans, complaints, etc. ;
  • a change in behavior, sometimes a form of aggression;
  • a feeling of disorientation and uncoordinated movements;
  • a state of depression;
  • the animal turns in circles;
  • the head tilts abnormally;
  • paralysis of the face or half of the body;
  • the dog shows signs of low vision or blindness;
  • the dog falls into a coma.

If you have the slightest doubt when you notice one or more of these symptoms, consult your veterinarian without delay, because these appear when the tumor has already reached a substantial size.

The veterinarian’s diagnosis

The veterinarian begins by carrying out an observation examination. It tests the dog’s behavior and reactions to assess symptoms.

The diagnosis can only be made by an MRI or a CT scan, these examinations making it possible to see with precision the tumor, its location and its extent. An ultrasound may be necessary if the tumor has grown from another organ, in other words in the case of a secondary brain tumour.

A blood test can then better identify the nature of the tumor, as well as a puncture of cerebrospinal fluid.

How to treat a brain tumor in dogs?

Unfortunately, it is very rare for a dog to be cured of brain cancer. The tumor is usually already well developed when the diagnosis is confirmed. On the other hand, by acting early enough, the veterinarian will be able to provide care that will slow the development of the tumour, improve the animal’s quality of life, and even perhaps allow it to recover.

Depending on the shape of the tumour, the solutions are variable:

  • for a malignant tumour, only treatment based on drugs can be administered to him in order to reduce his suffering and limit the effects of the symptoms during the months that remain to him to live.
  • for an operable benign tumour, surgery is the solution. It can remove the tumor and lead to remission.
  • for an inoperable benign tumour, the veterinarian will advise radiation therapy to prolong the dog’s life while temporarily reducing the effects of the tumour.

Unfortunately, a dog with a brain tumor has an average life expectancy of 1 to 18 months. If it can be operated or if it can undergo radiotherapy, its existence can be prolonged from 8 to 30 months.


Surgery removes a brain tumour. However, it is only possible if the tumor is located on the external part of the brain, if it is not infiltrating and especially if it is unique.

Radiotherapy treatment is generally recommended after surgery in order to completely eliminate the tumour.

Radiation therapy

Radiation therapy helps reduce the size of a tumor when it is not operable. It prolongs the existence of the dog while allowing him to suffer less thanks to the association of medicinal treatments.

Can a brain tumor in dogs be prevented?

There is no miracle formula to prevent a dog from developing a brain tumour. Unfortunately, the risk factor is everywhere. Some breeds are more affected than others, but any animal can be affected.

Ideally, it is advisable to ensure that your dog has a healthy lifestyle. Feed him a quality diet, watch his weight, and exercise him daily. Avoid contact with dangerous or toxic products and substances. Do not walk it in unsanitary or risky places and do not leave it outside unsupervised. Don’t let a minor illness or injury lie idle.

In the slightest doubt or if you notice a change in his behavior, consult the veterinarian in order to detect any anomaly quickly.

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