Lymphoma is a disease that targets the lymphocytes in the body. Lymphocytes are white blood cells that defend the body from foreign materials and substances like bacteria, viruses, and cancer. When a patient’s lymphocytes are attacked or malfunctioning, the body can start to shut down because it can no longer fight off infections.
Lymphocytes are located throughout the body. While lymphoma can target only one location, it often spreads because the lymphatic system is a network of tissues and organs that help rid the body of toxins, waste and other unwanted materials.
There are different types of lymphoma in dogs, as there are in humans. There are four distinguishable types recognized by veterinarians today. Each type of lymphoma is characterized by the part of the body affected.
The most common form of lymphoma in dogs is multicentric lymphoma, which affects the lymph nodes throughout the body. Commonly, dogs with multicentric lymphoma have enlarged peripheral lymph nodes, and they can also experience weight loss, anorexia, and lethargy. Lymph nodes located around the neck, chest, armpits, and behind the knees are the easiest to feel if swollen.
The second most common form of lymphoma, accounting for less than 10% of cases, is alimentary lymphoma. Alimentary lymphoma affects the gastrointestinal tract of dogs and is often localized in the intestines. As it targets the intestines, the dog’s stomach may ache and they may lose their appetite, vomit, experience diarrhea, or lose weight.
Mediastinal Lymphoma targets lymph nodes in the chest, creating growths that can affect a dog’s breathing. It may lead to shortness of breath and/or coughing due to lesions in the chest and possible accumulation of fluids. Dogs with this form of lymphoma may also show excessive thirst and increased need to urinate.
Any type of lymphoma that affects a dog’s body outside of the lymphatic system is extranodal lymphoma. This type of lymphoma often targets a specific organ, such as the lungs, skin, eyes, bones, kidneys, or nervous system. Cases can be severe and lead to difficulty breathing, skin sores, difficulty seeing, bone fractures, kidney failure, or seizures.
B-cell and T-cell Lymphoma
A subcategory of lymphoma has to do with whether the lymphoma affects B-cells or T-cells. B-cells and T-cells are types of lymphocytes that work together in the immune system. B-cells make antibodies to fight foreign substances, while T-cells fight cancer cells and monitor the immune response to foreign substances. B-cell versus T-cell lymphoma may affect your dog’s body in different ways. A test will guide you and your veterinarian to the best treatment plan by determining which type your dog has.
The symptoms associated with canine lymphoma vary and your dog may require multiple tests to determine the cause of their symptoms. With any illness, it is important to monitor your dog’s symptoms and establish an ongoing conversation with your veterinarian.