Why is Mast Cell Tumor Common in Some Dog Breeds?

Dogs are great pets to have because of how they are usually very hardy animals when compared to other domesticated pets. Most dogs, if given the proper care since the early stages of their lives, will most likely live for more than a decade healthily. But, just like humans, they too are prone to illnesses and health conditions that can prove to be fatal. Some of those are tumors.

Among the different types of tumors that dogs suffer from, mast cell tumor is quite common. In fact, there are some dogs that are actually more prone to it than other breeds are. But for us to find out why, let us learn more about what a mast cell tumor is, how it affects your dog, and how you can manage or even treat this condition to lengthen your pet’s lifespan.

Mast cells are white blood cells

Before we get to learn anything else, we must know what a mast cell is. Mast cells are actually certain types of blood cells that can be found in many parts of the body. What makes them different from the regular blood cell that acts as the body’s natural defense system is that mast cells have a more specific role. Instead of being all-around white blood cells, these mast cells are actually allergy cells that have a role in how the dog responds to certain allergies.

When your dog is exposed to certain allergens, mast cells respond by releasing chemicals that are known to cause the allergic reactions we know of such as sneezing, itchiness, and runniness in the eyes or also in the nose. One of those chemical compounds is histamine, which is responsible for the most common types of allergic reactions. When it is released in large amounts, histamine can trigger dangerous reactions such as anaphylaxis. That is why most medicines made to treat allergies are antihistamines. 

Mast cell tumor is a type of tumor that is composed of those mast cells

We are going to be stating the obvious here, but mast cell tumors are tumors that are logically composed of mast cells that have mutated just as other types of cancers or tumors are caused by certain cells that have also mutated. Mast cells actually reside in connective tissues in the body, such as those in the nerves, which are quite close to external surfaces such as the skin. That why a dog suffering from mast cell tumors commonly has masses in the skin. But mas cell tumors can also affect other parts of the dog, such as its bone marrow or intestine.

Some breed are more prone to mast cell tumor than others

As mentioned in the introduction, there are breeds of dogs that are more prone to mast cell tumors than others are. Such breeds include Bulldogs, Pugs, Boxers, Terriers, Golden Retrievers, Labrador Retrievers, Beagles, and Bull Mastiffs. But the breed that usually has a higher risk of suffering from mast cell tumors is the Bernese Mountain Dog. Meanwhile, dog breeds such as Pugs, Bulldogs, and Boxers develop mast cell tumors that are not as aggressive as the ones you see in other breeds. Labrador retrievers tend to suffer from a more dangerous type of mast cell tumor.

Genetic Lottery

If you are wondering why some dog breeds are more prone to suffering from mast cell tumors, the easiest answer to that is that this disease can be congenital in the sense that certain dog breeds naturally suffer from it due to their genetic makeup. 

Pure breeds such as Pugs, Bulldogs, Labradors, and the other breeds mentioned in the previous item have been bred for hundreds or even thousands of years from pure bloodlines that are not as diverse as ones you see in other dog breeds. As such, if some of their far-off ancestors suffered from mast cell tumors, there is a chance that such a trait will easily pass off to the next generation and again to the following generations if they are bred with other dogs that are also prone to this condition. In the case of the Bernese Mountain Dog, it is more prone to this condition precisely because of how narrow its ancestral tree is.

Mast cell tumors usually occur in older dogs

You do not always have to worry about mast cell tumors because this condition usually occurs when the dog is already getting old. The mean age for this condition is about eight years due to how it occurs in some dogs that are already over a decade old. However, there are instances when it has occurred in puppies that are only about a few months old or in young dogs that are only over a year old.

Mast Cell tumor can develop in different areas of the dog’s body

While mast cell tumors are commonly found on the dog’s skin, they can actually occur in different parts of their body. They are usually bumps or lumps on the dog’s skin because of how this tumor can occur just under the skin or any other exterior surface. However, you can also find this in other parts of the dog’s body and may, in fact, be found in internal organs.

There are no specific characteristics to this tumor

Mast cell tumors have no specific characteristics as one tumor may be different compared to another. Some of these tumors grow rather quickly and may appear in almost an instant. Meanwhile, there are other mast cell tumors that slowly and steadily grow until they are noticeable. Some are small, and others are large. There are also some tumors that actually fluctuate and may suddenly grow or shrink. It really varies.

Mast cell tumors can cause other conditions

The chemicals released by mast cell tumors can actually be harmful when they get into the dog’s bloodstream. As such, these tumors can cause other conditions and may also worsen some other conditions that your dog is already suffering from. They can form ulcers in the dog’s stomach, which eventually causes loss of appetite and then lead to lethargy and rapid weight loss. The tumor can also enlarge other organs due to fluid buildup. Meanwhile, in cases that are milder, the release of the chemical can cause allergic reactions even though the dog was not exposed to any allergens.

Idiopathic Causes

Similar to how certain breeds are more likely to suffer from mast cell tumors than others are, there are no exact explanations as to how this type of cancer is formed. It can be due to hereditary issues, especially if the mast cell tumor is a common denominator in the dog’s ancestry. Sometimes, it can be due to a combination of factors such as genetics, environment, and food.

Surgery is the best treatment

There are a lot of different treatments that can help manage the symptoms related to mast cell tumors. Antihistamines are prescribed to help manage the allergic reactions caused by this kind of tumor. However, aggressive surgery is often the best treatment for mast cell tumors. But before that, the vet will most likely conduct an examination that will determine how successful the surgery can get.

In cases when the primary area affected by the tumor tends to be too sensitive, vets will most likely prescribe chemotherapy instead of surgery. This treatment may provide short-term relief to your dog, but there is no guarantee if it will actually treat the mast cell tumor.

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Lovelia Horn

I’m a certified crazy dog mom, a physical therapist (for hoomans), writer, animal rescuer, and foster home provider. Together with my hubby Ryan, I’ve fostered and helped look for forever homes for over a hundred shelter dogs in the Southern Illinois area. I mostly work with Puppy Rescue 911, Inc., a certified animal rescue organization based out of Chester, IL (home of Popeye!)

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