Lymphoma in dogs is one of the most common types of cancer affecting our canine companions. It happens when a type of white blood cell, called the lymphocyte, starts to grow and multiply uncontrollably. 

The lymphatic system runs all throughout your dog's body. This includes the spleen, bone marrow, lymph nodes, and other related organs. When these cells turn cancerous, they can spread through the system.

Here, we'll talk about lymphoma and everything you need to know about it. By the end, you'll get a good understanding of what it is, what it looks like, and how it's treated. 

What Are the Types of Lymphoma in Dogs?

Vets generally classify lymphoma in dogs according to where it is and how it affects the body. 

Multicentric Lymphoma

The most common type of lymphoma in dogs. It usually starts as painless swelling of the lymph nodes all over the body. Multicentric lymphoma in dogs covers about 80 to 85% of all cases. 

Aside from the swelling of several lymph nodes in the neck, shoulders, and knees, dogs may also develop fever, weight loss, changes in appetite, and lethargy. 

Alimentary Lymphoma

The second most common form is alimentary lymphoma. This is also called gastrointestinal lymphoma in dogs. It usually targets the stomach, intestines, and other key parts of the digestive tract. 

Common symptoms of gastrointestinal lymphoma in dogs include frequent vomiting, diarrhea, abdominal pain, loss of appetite, and lethargy. 

Mediastinal Lymphoma

Mediastinal lymphoma affects the lymph nodes in the chest cavity and sometimes the thymus gland. Dogs may develop symptoms related to these areas. This includes labored breathing, rapid breathing, coughing, fluid buildup in the chest cavity, and lethargy. 

Extranodal Lymphoma

While rare, extranodal lymphoma in dogs can affect organs outside the lymphatic system. This includes the skin, eyes, lungs, kidneys, and nervous system. 

Common signs include lumps and red patches on the skin, cloudiness and redness on the eyes, excessive drinking and urination, and seizures and loss of coordination. 

Causes of Lymphoma in Dogs

Generally, the causes of canine lymphoma have still not been completely uncovered. However, there are some risk factors that have been suspected.

Genetics and Breed Predisposition

Some breeds are more likely to develop lymphoma.

• Rottweilers

• Doberman Pinschers

• Boxers

• Golden Retrievers

• Scottish Terriers

• Saint Bernards

• Basset Hounds

While these dogs have an increased risk, other breeds can also be affected. 

Environmental Factors

Dogs exposed to certain chemicals and pollutants may also be at risk of canine lymphoma. Herbicides, pesticides, cigarette smoke, and industrial chemicals are the common factors that have been suspected in cases of lymphoma in dogs.

Immune System Dysfunction

A suppressed and weakened immune system can also be a risk factor for canine lymphoma. It may have a harder time spotting and destroying the abnormal cells before they rapidly multiply. However, this isn’t a guaranteed cause. 

Age

Age is another factor. Lymphoma commonly affects middle-aged dogs and seniors. It can also occur in younger dogs, but it is not as common. 

What Are the Early Warning Signs of Lymphoma in Dogs?

One of the tricky things about lymphoma is that early on, dogs may seem completely fine. It can be challenging to detect the disease early on. As the disease progresses, some early warning signs of cancer start to show. These include: 

• Swollen Lymph Nodes. These are firm, round lumps you might feel under the jaw, in front of the shoulders, or behind the knees.

• Loss of Appetite and Weight Loss. The cancer and symptoms can affect your dog’s metabolism, causing nausea and loss of appetite. Because of this and malabsorption from lymphoma, dogs can also lose weight. 

• Lethargy and Fatigue. Dogs with lymphomas often become tired as their bodies are working harder to fight off the disease. They may sleep more and lose interest in playing.

While each type may develop differing symptoms, these are the common early signs pet owners can expect to notice.