Home » Pet Health » Cancer 101 » Unusual Lymph Node Symptoms


Lymph nodes are good indicators that the immune system is busy. The general appearance of lymph nodes changes when the body fights an infection. For example, if you have ever had a cold that made your jaw on either side of the neck feel swollen when touched, those were swollen lymph nodes!

Lymph nodes become enlarged due to the build-up of lymphatic fluid, debris, and white blood cells. White blood cells migrate to the lymph nodes found closest to an infection site and work to fight off the infection. There are a variety of places lymph nodes can swell on your pet’s body:

    • Submandibular: These are the most common swollen lymph nodes found in dogs. They are located directly underneath the jaw by your pet’s neck. Pet owners commonly identify these lymph nodes as swollen due to their prominent location.
    • Pre-scapular: These lymph nodes are on either side of your pet’s chest in front of the shoulder area.
    • Axillary: The axillary lymph nodes sit in your pet’s armpit, under the front legs.
    • Inguinal: Inguinal lymph nodes are in your pet’s groin area, near the back legs.
    • Popliteal: These lymph nodes lie in the back of your pet’s knee.

Lymphocytes and lymph fluid will commonly utilize the lymph node closest to the damaged location during an infection or disease. Therefore, identifying where your pet’s swollen lymph nodes are is a significant step in determining the origin of the disease.

The vet will check for lymph node enlargement in the throat, knees, or abdomen. Generally, only one or two lymph nodes will swell. However, when the body fights a severe infection, you may find swollen lymph nodes all over your pet’s body. Significant swelling of lymph nodes in your pet’s body can be a sign of cancer.

It is important to perform regular checks on your pet’s body for abnormalities in their lymph nodes. Become familiar with the nodes’ normal size while your pet is healthy so you can easily spot when there is an enlargement in the area. If you notice a change in the lymph nodes, speak to your vet.

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Last Updated: October 20, 2022

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The following sources were referenced to write the content on this page: 

Bogoslowski, A & Kubes, P 2018, ‘Lymph nodes: the unrecognized barrier against pathogens’, ACS Infect Dis, vol. 4, no. 8, pp. 1158-1161.

Duenne, AA & Werner, JA 2000, ‘Functional anatomy of lymphatic vessels under the aspect of tumor invasion’, Recent Results Cancer Res, vol. 157, pp. 82-89.

Sojka, DK, Lazarski, CA, Huang, Y-H, Bromberg, I, Hughson, A & Fowell, DJ 2009, ‘Regulation of immunity at tissue sites of inflammation’, Immunol Res, vol. 45, no. 2-3, pp. 239-250.

Ku, C-K, Kass, PH & Christopher, MM 2017, ‘Cytologic-histologic concordance in the diagnosis of neoplasia in canine and feline lymph nodes: a retrospective study of 367 cases, Vet Comp Oncol, vol 15, no. 4, pp. 1206-1217.

The Pet Cancer Foundation’s medical resource for pet owners is protected by copyright.

For reprint requests, please see our Content Usage Policy.