Home » Pet Health » Cancer 101 » Cancers of the Lymphatic System


Cancer that begins in the lymphatic system is known as lymphoma. It is a kind of blood cancer that develops when white blood cells (called lymphocytes) grow out of control. Lymphocytes are a part of the immune system that travel via the lymphatic system and help evade infections. Lymphomas affect the function of lymph nodes and impair the body’s ability to fight infection and cancer. Lymphomas can also easily travel to different tissues and organs, potentially leading to cancer development in other body parts.

There are four main types of pet lymphoma:

    1. Multicentric lymphoma: This is the most common form of lymphoma and arises in your pet’s lymphoid tissues, which can include the lymph nodes, bone marrow, or spleen.
    1. Alimentary lymphoma: Approximately 10% of pets are diagnosed with this cancer, which primarily affects your pet’s intestinal system, including the upper and lower gastrointestinal tract, liver, and pancreas.
    1. Mediastinal lymphoma: This is a rare form of lymphoma. It arises out of mature immune cells called B cells. For this reason, the cancer is generally in your pet’s chest or thymus (a gland that sits just under the breastbone and makes lymphocytes).
    1. Extranodal lymphoma: This term refers to lymphoma in a specific organ, like the skin or kidneys.

Any pet can develop lymphoma, but the most common breeds of dogs prone to this kind of cancer are Boxers, Dobermans, Golden Retrievers, and Rottweilers. The types of lymphomas most likely to develop in dogs include:

    • Marginal zone lymphoma
    • Peripheral T-cell lymphoma not otherwise specified
    • Nodal T-zone lymphoma
    • Lymphoblastic T-cell lymphoma
    • Diffuse large B-cell lymphoma (DLBCL)

DLBCL accounts for approximately 70% of canine lymphomas.

In cats, lymphoma is also the highest reported cancer and cats are most prone to develop lymphoma of the intestinal tract (alimentary lymphoma). However, some reports indicate an increase in mediastinal lymphomas in Siamese and Oriental breeds.

Unfortunately, there is currently no one known cause of lymphoma. Studies have shown that exposure to carcinogenic agents–chemicals connected to cancer development–will heighten the risk of developing lymphoma. Similarly, genetics and immune-suppressing drugs might play a role.

Appreciating the different types of lymphatic cancers and their potential causes can help you to understand your pet’s risk of developing lymphoma. You can also learn about possible signs of lymphoma so you can have your vet check your furry friend early. Education, regular checkups, and a healthy lifestyle are great ways to reduce your pet’s cancer risk so you can share many happy and healthy days ahead.

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Last Updated: October 21, 2022

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