Lymphoma in dogs

Written by Dr Andrew Miller MRCVSDr Andrew Miller MRCVS is an expert veterinary working in the field for over 10 years after graduating from Bristol University. Andy fact checks and writes for Pure Pet Food while also working as a full time veterinarian. Pure Pet FoodPure Pet Food are the experts in healthy dog food and healthy dogs featured in media outlets such as BBC, Good Housekeeping and The Telegraph. Working with high profile veterinary professionals and nutritionists, Pure Pet Food are changing dog food for the better. - Our editorial process

A common, progressive type of cancer in both humans and dogs, a lymphoma diagnosis is a terrifying prospect for any dog owner. It can affect all dogs, but middle-aged and senior pooches are usually more susceptible to this type of cancer.

Even though lymphoma is experienced by many, both people and pooches, we still have little understanding of the disease itself. Research is constantly underway in an attempt to learn more about this awful condition.

What is lymphoma in dogs?

Lymphoma is actually a diverse collection of several cancers, and it sparks from the white blood cells in the immune system, which help battle infections, becoming abnormal. These white blood cells are labelled the lymphocytes.

Lymphocytes exist in high amounts in the lymphatic system, which primarily includes organs heavily involved with the immune system.

Most commonly, the cancer impacts the lymph nodes, which are located in the neck, behind the knees, chest, armpits and in the groin. Lymph nodes are crucial to a dog’s immune system, but they’re extremely tiny and should be pretty difficult to find and feel for on your dog.

Also, the bone marrow, thymus and spleen are other common areas for the cancer to arise, although it’s possible for any organ to be affected.

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Canine lymphoma is not one definitive cancer, it exists in many different forms which all differ in their symptoms, survival rates and severity.

What are the main types of lymphoma in dogs?

Although there are various other types of lymphoma, there are four types that generally affect our pups, which are multicentric, alimentary, mediastinal and extranodal. All four of these types affect different parts of the body and occur in different ways. No one form is the same.


Impacting the majority of dogs that suffer with this cancer, multicentric lymphoma is prevalent in over 75% of dogs affected with lymphoma. Primarily, this type of lymphoma affects the lymph nodes and can even impact several at the same time.

Consequently, this means that the most recognisable symptom of multicentric lymphoma is noticeably enlarged lymph nodes. The lymph nodes should also feel firm to touch. Although swollen lymph nodes are the main symptom of multicentric lymphoma, your dog could also experience fatigue, fever, dehydration and be incredibly weak as a result.

Alimentary (gastrointestinal)

Not nearly as common as multicentric, alimentary lymphoma occurs in the gastrointestinal tract. Signs of this form of lymphoma are mainly all stomach related, primarily vomitingdiarrhoea and fatigue.

Significant weight loss can even occur as absorption of nutrients is considerably hindered due to these symptoms. Diagnosis can be a lot trickier than other types of lymphoma as the symptoms could be indicative of many other medical conditions.


Quite a rare form, mediastinal lymphoma targets the chest region, and this is where all the symptoms arise. Typically, it’s caused by an enlarged thymus or swollen lymph nodes.

Symptoms of mediastinal lymphoma usually manifest through breathing problems as fluid builds up within the chest and adds pressure. Sometimes, dogs suffering with this may appear swollen in the face too, in addition to an increased thirst.


Extranodal lymphoma is a form that impacts a particular organ, such as the kidneys, lungs or eyes. Whatever organ the cancer targets will cause varying symptoms, but the most common organ for extranodal lymphoma to target is the skin.

More specifically, when lymphoma occurs on the skin, it’s referred to as cutaneous lymphoma. Although cutaneous lymphoma is relatively rare, symptoms of this form often show itself in ulcers, raised lumps, red patches, scaly skin and hair loss.

Regarding other forms of extranodal lymphoma, the symptoms will correlate to the area that the cancer is affecting. For example, if the cancer is in the lungs, respiratory problems will ensue.

What causes lymphoma in dogs?

Despite various types of canine lymphoma occurring in so many dogs, knowledge of the overall disease is relatively limited. It’s unclear why some pups suffer with this awful disease and some don’t.

Research is constantly underway to try and determine the cause. Theories include viral infections, genetic predisposition and even physical factors such as exposure to chemicals.

How is lymphoma in dogs diagnosed?

Previously, lymphoma was deemed as just one type of cancer. However, after it was recognised that several completely different types of lymphoma exist, the need for separate diagnosis and treatment methods has become apparent.

Diagnosis typically occurs in one of two ways, both requiring a sample to be taken. Using a fine needle to gather cells from a swollen area is a quick and relatively easy procedure, used when the lymph nodes are clearly visible and enlarged. This shouldn’t be very painful for your dog and will be over almost instantly.

On the other hand, when a larger sample size is required, a biopsy will be carried out. Your pup will likely be under anaesthetic for this procedure, but it’ll provide the vet with an incredibly precise examination of the cancerous tumour.

Often, in the event of potentially cancerous internal lymph nodes and organs, x-rays and ultrasounds may be necessary to gain an effective diagnosis. As a result, all of this allows the vet to determine the optimum method of treatment for each specific case of lymphoma.

How is lymphoma in dogs treated?

Exploring treatment is a great option for a pooch diagnosed with any form of lymphoma, providing your pooch with the opportunity to feel like themselves again despite their illness. Unfortunately, although the treatment can significantly help your dog, a full cure is extremely rare.

Chemotherapy is the main protocol for treating lymphoma. Working by targeting the cancerous cells and reducing the aggressiveness and size of the tumour, chemotherapy can dramatically benefit your dog’s condition.

Negative side effects of chemotherapy are minimal for dogs, unlike the way it impacts humans. Hair loss is relatively unlikely, only specific breeds like the Poodle and Bichon Frise tend to experience this reaction to chemotherapy. Other side effects such as moderate sicknessdiarrhoeafatigue and a loss of appetite can occur as a result, but they’re usually not too severe.


Due to the limited knowledge of lymphoma, the survival rates for dogs are uncertain. As there are several types of the cancer, the prognosis varies massively. Alongside this, it’ll also depend on how far along the cancer progressed before treatment began.

After treatment, many dogs accomplish a total remission. This means that the cancer cells are undetectable in the body and the symptoms have diminished, however, the cancer could still be present in the body.

Remission doesn’t equate to your dog being cured. A cure means that the disease has been completely eradicated. Consulting a vet and working out a treatment plan will likely extend your dog’s life, but most will unfortunately develop the cancer again. Treating it for the second time can be a lot trickier, as the cells can be significantly more resilient to the treatment.

Sadly, lymphoma is very common and it can be fatal. Hearing the news that your beloved furry friend has received this diagnosis will be heartbreaking, but seeking treatment immediately can give your dog a returned vibrancy and increase their time with you by a substantial amount. Being aware and proactive with your pup’s condition is the best thing an owner can do.

  1. Canine lymphoma: A review Veterinary Quarterly, 36, (2), March 2016, 76-104,