Overview of Feline Lymphosarcoma (Lymphoma)
Lymphosarcoma (lymphoma) is a malignant cancer that involves the lymphoid system. In a healthy animal, the lymphoid system is an important part of the body’s immune system defense against infectious agents such as viruses and bacteria. Lymphoid tissue normally is found in many different parts of the body including lymph nodes, liver, spleen, gastrointestinal tract and skin.
Classification of Lymphosarcoma in Cats
Lymphosarcoma is classified according to the location in the body in which the cancer begins.
Currently in the USA, gastrointestinal lymphoma is the most common form. Historically, mediastinal lymphosarcoma occurred most frequently in young cats infected with feline leukemia virus, but reports of young cats with FeLV positive lymphoma are less common than in the early 1980’s. These cats may have involvement in other areas of the body, such as the bone marrow. The gastrointestinal form of lymphosarcoma most commonly affects older cats that are not infected with the feline leukemia virus.
Recently, research has shown that cats that live in smoking environments are 2 to 4 times more likely to develop lymphoma than cats that live in smoke-free environments. The exact mechanism is not understood.
Lymphosarcoma occurs in middle-aged to older cats. No breed of cat is known to be at a higher risk for lymphosarcoma than other breeds. Males and females of both species are affected equally. Infections with both feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) have been shown to increase the risk of developing lymphosarcoma. Cats infected with FeLV often develop lymphosarcoma at a young age.
Symptoms in cats with lymphosarcoma depend primarily on the location of the tumor cells. Symptoms include enlargement of external lymph nodes, vomiting, diarrhea, loss of appetite, weight loss, lethargy, difficulty breathing and increased thirst or urinations. Cutaneous lymphosarcoma can cause redness or flakiness of the skin, ulceration (especially near the lips and on the footpads), itchiness (pruritus) or lumps in the skin.
Diagnosis of Lymphosarcoma (Lymphoma) in Cats
Diagnostic tests are needed to identify lymphosarcoma and exclude other diseases. These tests may include:
Treatment of Lymphosarcoma (Lymphoma) in Cats
Seek veterinary care promptly if you detect lumps below your pet’s skin in the neck, shoulders, armpits, or back legs or if your pet has vague symptoms of illness such as loss of appetite, lethargy, and weight loss. Watch your pet for vomiting, diarrhea and development of infections.
The best prevention is to avoid infection of cats with FeLV and FIV by limiting their exposure to other cats of unknown status. Also, smokers should consider quitting smoking or only smoking outside.
In-depth Information on Lymphosarcoma (Lymphoma) in Cats
Other diseases can mimic the signs of lymphoma. Some of these may include: