Dog tumor

Many tumors can afflict our dog friends, and if this term can frighten many owners, it is important to note that the word tumor does not systematically refer to cancer, as one might fear.

Tumors are masses, growths, bumps and any other protuberance that can be located both on the dog's skin and on its internal tissues. Today, I propose to learn more about malignant and benign tumors of the dog, in order to discover what they imply for the health of our four-legged companions according to their nature.

 

What are dog tumors?

A tumor, or tumor mass, is a swelling of tissue. The term comes from the Latin "tumere" which means "to swell". Also, the term tumor alone does not imply any particular disease, cause, or organ of the dog.

This means that any type of tumor can be found on and in a dog's body, of any size and from a wide range of causes. A dog can also have multiple tumors, or only one tumor, without this being a factor in its severity.

Also, the symptoms caused by a tumor are multiple, as are the possible treatments. The appearance of a tumor can also vary quite a bit depending on its nature, ranging from a simple wart to a mass of several centimeters.

The prognosis of the dog generally depends on the phenomenon that caused the tumor to form, but also on the location and size of the tumor.

 

Benign tumors of the dog

Benign tumors are more frequently encountered than cancerous tumors.

Warts, papillomas in dogs
Warts are benign tumors that are frequently found in dogs. They can affect the mucous membranes (mouth, conjunctiva and genitals), as well as the skin and the paw pads. They are caused by an infection with a specific virus genus, the papillomavirus. In fact, the medical term for a wart is papilloma.

In young dogs (less than 2 years old), very virulent forms of oral warts can be seen, while older dogs (over 7 years old) more often have more discrete skin warts. It is estimated that all dogs will be infected with HPV in their lifetime, but only those with weak immune systems (young, old or sick dogs) will develop warts.

Dog warts are recognizable by their typically rough and irregular "cauliflower" appearance which makes them, it must be said, particularly repulsive. However, there are also smooth and not very prominent papillomas, which can grow in the form of patches, as well as inverted warts which form small craters, often located on the belly.

They are usually pigmented, can be of different shades and sizes, and grow singly or in clusters. Although they are unsightly, warts are harmless in the vast majority of cases and will eventually disappear on their own.

Cutaneous histiocytoma in dogs
A cutaneous histiocytoma is a tumor that mostly affects young dogs under 2 years of age. This benign mass begins as a firm, well-circumscribed nodule, usually located on the head or limbs of the animal. Usually pink in color, the histiocytoma can sometimes become complicated into an ulcer and become infected, especially if it is located on a traumatic site. However, in most cases, this small tumor resolves itself after a few months.

Certain breeds of dogs are predisposed to the development of skin histiocytomas, such as the Dachshund, the English Bulldog, the Labrador, the Rottweiler and the Miniature Pinscher, to name only the best known. Multiple and persistent forms of cutaneous histiocytomas also exist, and are found in the Shar Pei.

Lipoma and cyst in dogs
The lipoma is a fatty tumor that appears most often in older and obese dogs, and affects preferentially females. However, all dogs can have one or more lipomas. Lodged just under the skin of the dog, often on the thighs or the belly, the lipoma is not really dangerous, but it can hinder the movements of the dog or be painful when it becomes too big.

It is nevertheless quite rare to have to treat a lipoma, the animal generally supporting it rather well, and not being bothered by the unsightly side of the mass - contrary to the master. In a generic way, a lipoma is a cyst, i.e. an organic cavity containing a more or less liquid substance. Cysts can be located on the dog's skin, like lipomas, or on its internal organs.

While a lipoma typically contains fat, a cyst can contain a wide variety of different substances depending on its nature, from simple sebum (sebaceous cyst) to parasites (echinococcosis). Most cysts are discovered incidentally during medical examinations and do not pose a health risk to the dog.

However, some internal cysts can grow to a considerable size and put pressure on the dog's organs, risking damage to them and causing pain.

 

 

Malignant tumors in dogs

Malignant tumors are cancerous masses that can appear on the dog's skin or internal organs and can affect any animal, although older animals are more prone to them. Unlike benign tumors, malignant tumors do not stop growing and do not disappear on their own.

The cells that compose them proliferate abnormally in an uncontrolled manner, eventually metastasizing, traveling through the dog's body to colonize other organs. It should be noted that cancerous tumors are only dangerous because of their ability to colonize the dog's vital organs.

For example, a skin tumor cannot directly kill a dog (unless it becomes very large and causes bleeding). On the other hand, if left untreated, it will fatally metastasize and reach the dog's heart, liver, lungs or brain, which will no longer be able to function properly and will lead to its death.

The most common malignant tumor in dogs is lymphoma, a particularly aggressive cancer of the lymphatic system. The masses form mainly in the dog's lymph nodes, but can also affect the tonsils and the spleen, and, more exceptionally, the heart, liver, intestine, kidneys, stomach, lungs, nervous system, skin and eyes.

Mastocytoma is the most common malignant skin tumor in dogs. It mainly affects adult dogs, preferentially Boxers, Carlins and Boston Terriers. In addition to lymphoma and mastocytoma, there are a large number of other malignant tumors that can affect dogs, especially older specimens.

 

Symptoms of tumors in dogs

Benign and malignant skin tumors are usually visible to the naked eye and form masses that can be felt by petting the dog. A benign skin tumor can rarely be distinguished from a cancerous one by a simple glance, and veterinary examinations are essential to characterize the mass and determine if it has potential malignancy.

A simple biopsy, taking a few cells from the tumor, usually removes the doubt. However, this examination is not necessary when the tumor is very characterized and easily recognizable, which is notably the case for papillomas (warts). Deep tissue tumors are difficult to diagnose and often have no symptoms until they interfere with the function of one or more organs.

The dog then presents specific symptoms depending on the organ affected: lung tumors (rare in dogs) cause breathing difficulties, liver tumors may manifest as jaundice, tumors of the peritoneum cause digestive disturbances... Sometimes, the dog will present a general depression, fever, intense fatigue or anorexia in case of malignant tumors.

Benign internal tumors may cause pain if they are large and compress certain organs. Like malignant tumors, they can sometimes cause specific disorders depending on the organs compressed when they interfere with their function and alter their vascularization, which remains rare.

 

 

 

Treatment and prognosis of tumors in dogs

Benign tumors usually do not require treatment except when they interfere with the dog's movement, compress organs, cause pain or are likely to become complicated. Masses in traumatic areas (e.g., between the toes) or those that tend to ulcerate are sometimes removed to rule out infection.

Similarly, certain benign tumors with malignant potential (which may develop into cancer) are often treated as a precautionary measure. The preferred treatment for tumors is surgery, which involves removal of the tumor. However, some tumors, especially warts, are sometimes treated with drugs that speed up their resorption.

Cancerous tumors are also treated with surgery when they can be removed. Anti-cancer treatments (chemotherapy and radiation) are often necessary to reduce the risk of recurrence. It should be noted, however, that cancers are often diagnosed late in the dog's life, at a stage when it is unfortunately impossible to cure the animal permanently.

However, treatment of the cancerous tumor remains essential to increase the animal's comfort by decreasing its symptoms, and often significantly prolongs its life. The prognosis of dogs with malignant tumors depends on the stage of the disease at the time of diagnosis. Since the detection of this type of mass is often late, the prognosis is rarely good.

In case of benign tumors, the prognosis of dogs is excellent. It is rare for this type of lesion to degenerate, and some masses disappear on their own.

 

FAQ

My dog has a tumor, is it serious?
A tumor is not always serious in dogs, and it is possible that it is a benign mass that will disappear on its own. To be sure, the dog should be taken to a veterinarian who will perform a biopsy if necessary to determine the nature of the tumor. It is important to act quickly: if the tumor is malignant, the sooner it is treated, the better the dog's prognosis.

How do you treat a tumor in a dog?
The treatment of a tumor depends on its nature. There are all kinds of tumors in dogs, both harmless and cancerous. Malignant tumors will require surgical removal when possible, potentially combined with anti-cancer treatments (chemotherapy, radiation, etc.). Benign tumors rarely need treatment because they are not dangerous and sometimes disappear on their own.

What is a tumor in a dog?
A tumor is a mass, a swelling of some tissue in the dog. The term tumor is very vague, and does not necessarily imply malignancy. Dogs can be affected by many kinds of tumors, most of which are quite benign.

How to differentiate between benign and malignant tumors in dogs?
It is often impossible to differentiate a benign from a malignant tumor in dogs at a glance. Veterinary examinations, including a biopsy, are usually necessary. However, some tumors are very clear: most warts are benign tumors that are often easily recognized.

The presence of a visible tumor on or under a dog's skin can be very worrying for a dog owner, as this type of symptoms often makes one think of cancers. In reality, there are many benign tumors in dogs, which do not present any danger to their health and often disappear on their own after a few months.

To determine if a tumor is benign or malignant, it is essential to take your dog to a veterinarian who will perform a few tests to make sure your dog is safe or, in case of a cancerous mass, will implement an appropriate treatment.