Understanding the Differences in the Types of Canine Lymphoma

This post will go over all of the base questions about what those different types of lymphoma do and how they affect a dog’s body after diagnosis—starting with some of the more simple to understand questions and moving up to the more complicated.

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B-Cell and T-Cell

B-cells and T-cells are both main factors in your dog’s immune system. When working properly, they both defend the body in their own way by getting rid of viruses and bacteria in the system.

B-cell

B-cells protect the body by developing antibodies, something you’ve probably heard about at some point, but if you’re unclear here’s how they work. Antibodies are a protein that is developed to respond to a command in the immune system triggered by an Antigen. Antigens are proteins that normally exist on the surface of bacteria or viruses. The antibody that the B-cell creates attaches itself to the antigen and then either destroys the virus itself or calls other cells in the immune system to destroy the virus.

B-cell Lymphomas can be either slow developing or aggressive depending on the category that the cancer presents itself in.¹

B-cells respond better to most therapies than T-cells usually do, and B-cell lymphoma usually leans itself more towards large-cell presentation in the body. If your dog has been diagnosed with a small B-cell lymphoma you should count that as a blessing, they’re the most likely to respond well to the treatment.

T-cell

T-cells are another important part of the immune system. They target and destroy specific types of viruses or bacteria. Each T-cell is designed to get rid of one kind of threat. They act as a specialized attack force to protect the body from bigger threats.²

T-cell lymphomas are often more aggressive than B-cells and typically lean more towards the small-cell development. Though there is also a t-zone cell lymphoma that has a much more lenient threat to the body. T-zone lymphoma has a much better survival rate without much aggressive treatment, anywhere up to three years.³

T-cell lymphomas are able to be found in each of the categories below as well.¹

Indolent lymphomas

Indolent lymphomas are variations on lymphoma that can lead to different levels of intensity for managing the disease. For some patients with an indolent lymphoma form, treatment may become more flexible and not as time-sensitive. For example, t-zone cell lymphoma has a much more lenient threat to the body. T-zone lymphoma has a much better survival rate without much aggressive treatment, anywhere up to three years.³ 

While indolent lymphomas that originate in a B-Cell case, typically Marginal Zone Lymphoma (MZL) will respond best to treatment including the removal of the spleen more than other forms of lymphoma would. 

You can learn more about indolent lymphoma types in our blog here.

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Small Cell vs Large Cell

The size of the cell, small or large, in your classification can tell you some helpful information.

Small Cell lymphoma allows you to take a moment to breathe and process. Small cell diagnoses tend to lend a little bit more time to the pet. Not to say that you have all the time in the world, but you have more space to consider your options.

Large Cell lymphoma is a lot less forgiving. It is considered aggressive and is fast moving. A large cell diagnosis means that more of your pet’s body is being attacked by the cancer cells that are pretending to be helping the immune system. If left untreated, large cell lymphoma can prove fatal within 6-8 weeks.⁴

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Categories

Cancer has a tendency to develop the same cells in different ways. Lymphoma is no different. There are 4 main categories of how lymphoma presents itself in the body. The cells will mutate in the same way inside, but where they are located makes for a different experience that your dog will go through.

Multicentric

This is also referred to as systemic lymphoma. Multicentric means that the lymphoma is in multiple lymph nodes around the body. Rather than being localized to one lymph node area, the cancer cells are able to develop all over the body. This is the most common form of lymphoma, accounting for anywhere between 80-85% of all cases in dogs. Multicentric lymphoma can show itself in both B-cell and T-cell forms depending on the case.

Treatment for Multicentric lymphoma is incredibly important, the median length of time that a dog can survive post diagnosis without treatment is around 30 days. Treatment typically consists of a chemotherapy combination that we go into more detail about in our treatments post. When your pet completes the chemotherapy treatment, they can live happily in remission for as long as 2 years on average.⁵

Alimentary / Gastrointestinal lymphoma

Alimentary lymphoma affects the gastrointestinal tract. Oftentimes this is a T-cell variant of lymphoma. This form is much rarer than Multicentric; Alimentary Lymphoma only accounts for 5-7% of all canine lymphoma cases. The symptoms of Alimentary lymphoma also tend to be mistaken for general dog illness—a dog throwing up or having diarrhea can be caused by a lot of other factors—which makes this particular form of lymphoma a lot more difficult to diagnose.

This form can exist in conjunction with other forms of lymphoma or entirely on its own. The survival rate tends to be shorter than multicentric lymphoma due to the large portion of dogs diagnosed with Alimentary lymphoma having T-cell variants, which don’t respond as well to treatment as a pet parent would like.

Mediastinal

While this is not the most common form of lymphoma, it can be found in partnership with others. Around 22-36% of all lymphoma cases have some factor of mediastinal lymphoma acting as a part.⁶

This type of lymphoma affects the chest cavity, more specifically the cardiothoracic region. The development of lymphoma in this region restricts breathing and lung functions. Because of this, lack of treatment is fatal very quickly.

When combined with other categories, this form presents itself through large T-cell variants. The damage produced is catastrophic and quick.⁷

There is also Primary Mediastinal Lymphoma which presents itself more commonly in b-cell types.¹

Extranodal

This is the rarest form to be found completely by itself. Extranodal is exactly what it sounds like, when lymphoma presents itself outside of the lymph nodes. This can happen anywhere in the body like bone marrow, liver, eye tissue, skin, etc. Typically, dogs with extranodal lymphoma will experience degeneration on whatever organ is involved.⁸

The most common extranodal form is cutaneous, meaning on the skin, which is seen through reddened lumps on the skin and itching caused by the growths.

Cutaneous lymphoma 

The most common extranodal form is cutaneous, meaning on the skin, which is seen through reddened lumps on the skin and itching caused by the growths. The most common form of cutaneous lymphoma is epitheliotropic, though there is no known cause for why epitheliotropic lymphoma develops. 

You can learn more about cutaneous and epitheliotropic lymphomas in our blog here.

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If your pet has been diagnosed with one of these recently,

We’re really sorry to hear that. It’s never pleasant to hear a loved one has cancer, especially when that loved one doesn’t have the ability to understand what they’re going through fully.

We want to help get you through this process the best way we can, and our technology allows us to streamline the treatment process by using AI to help your pet receive the best chemotherapy treatment for their specific form of lymphoma.

Find out how you can get your vet involved with ImpriMed here.