What is Lymphoma in Cats?
What is it?
How is it Treated?
Breed Predispositions
Certain breeds, such as Siamese and domestic shorthair cats, may have a slightly increased risk of developing lymphoma.
Introduction
When Sarah first brought home her rescue cat, Jasper, she was committed to giving him the best life possible. Regular vet visits, playtime, and a healthy diet were all part of the plan. However, a few months into their journey together, Sarah noticed that Jasper seemed to be losing weight and appeared lethargic. Concerned, she made an appointment with their veterinarian. After a series of tests, Sarah was given the heartbreaking news: Jasper had been diagnosed with lymphoma.
Lymphoma is a cancerous tumor that starts in the cells of the immune system. Cats are prone to developing lymphoma because of their genetic makeup. Domestic shorthair cats are especially susceptible to lymphoma because they lack a gene called Rag1. This gene helps prevent lymphocytes from becoming malignant.
Lymphoma is aggressive cancer that occurs most often in older domestic cats. However, it is the most common cancer found in adult felines. Cats are usually diagnosed with lymphoma because they develop enlarged lymph nodes around the abdomen, neck, and head. Other symptoms include loss of appetite, weight loss, lethargy, vomiting, and diarrhea.
Types of Lymphoma in Cats
There are two types of lymphomas: Hodgkin’s disease (HD) and non-Hodgkin’s lymphoma (NHL). HD is most common in cats over ten years old, whereas NHL is most common in younger cats.
Both types of lymphoma may be inherited, meaning that some cats are genetically predisposed to develop them. Other risk factors include exposure to certain chemicals, radiation therapy, and infections.
Causes of Lymphoma in Cats
Cats develop lymphoma when their immune system fails to recognize cancerous cells as foreign invaders. This happens when their body cannot fight off infections and diseases. Lymphoma is often found in older cats, especially those over ten years old. It is a cancerous tumor that develops in lymph nodes.
Feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) cause lymphoma. These viruses are spread via saliva and urine. They can also be transmitted through blood transfusions or sharing needles for injections. Exposure to FeLV or FIPV increases the risk of developing the disease.
Cats infected with FeLV have a higher risk of developing lymphoma than those without the virus. The same holds for FIV-positive cats.

Other factors include genetics, age, breed, diet, lifestyle, stress, and exposure to environmental toxins.
Symptoms of Lymphoma in Cats
Gastrointestinal lymphomas are the most common type of feline lymphoma. This is one of the most common types of lymphoma found in cats; 50% to 70% of felines are affected. They affect older cats and are most commonly located in the stomach, small intestine, large intestine, cecum, and colon. These tumors grow slowly and cause weight loss, vomiting, and diarrhea.
Other symptoms include lethargy, weakness, fever, coughing, sneezing, lack of appetite, depression, excessive drinking, and urination. In addition, cats sometimes develop enlarged abdominal organs such as the liver and kidneys.
Mediastinal lymphomas occur primarily in young cats and are usually found near the heart. They are less common than gastrointestinal lymphomas and are typically associated with poor immune function.
Signs include difficulty breathing, coughing, wheezing, shortness of breath, labored breathing, increased respiratory effort during exercise, and rapid heartbeat. If left untreated, mediastinal lymphomas can lead to death within weeks.
Renal lymphomas are rare in cats. They are thought to originate in the kidney and spread to nearby tissues. Symptoms include decreased appetite, vomiting, dehydration, blood in urine, pain around the urethra, and sudden onset of blindness.
Diagnosis of Feline Lymphoma
When diagnosing lymphoma in cats, it’s essential to rule out other conditions first. This is especially true if you suspect the cat has leukemia.
A veterinarian might recommend diagnostic tests such as x-rays, ultrasound scans, and biopsies to help diagnose lymphoma in cats.
X-ray

X-ray images show if any tumors and abnormalities are growing in the bones, lungs, heart, spleen, pancreas, liver, kidneys, bladder, intestines, or other internal organs.
If your cat needs X-rays, bring them in early enough to allow adequate time for the exam. The earlier you take your cat in for an x-ray, the better the chance of catching any abnormalities.
When taking X-rays, ask your veterinarian to use the lowest possible dose. This helps protect your pet’s health and reduces radiation exposure.
Remember to ask your vet about the risks associated with X-rays. Some cats may experience mild discomfort during the procedure, but most find it painless. Your veterinarian should tell you when to expect results and when to return to pick up your cat.
Biopsies
If you suspect your cat has lymphoma, your veterinarian may recommend a biopsy. This involves taking tissue samples from suspicious areas of the body. Your vet will use a needle to remove cells from the affected area. Then they will send these cells to be examined under a microscope.
This process helps confirm the presence of lymphoma. Once verified, your vet will discuss treatment options with you.
Ultrasound
Ultrasounds are used to diagnose lymphomas in cats. Ultrasounds are painless, noninvasive tests that use sound waves to create images of internal organs. They’re safe, inexpensive, and relatively quick.
Ultrasounds are especially useful for detecting tumors because they can detect masses deep within the body. This makes them ideal for diagnosing cancers that are hard to find, such as those in the abdominal cavity.
Ultrasound exams are usually performed by veterinarians who specialize in ultrasound imaging. The veterinarian uses a handheld transducer to send ultrasonic waves through the cat’s body. These waves bounce off any abnormalities and return to the transducer, where they are converted into electrical signals.
These signals are sent to a computer screen, which creates an image of the inside of the cat’s body. The photo shows the location and size of any abnormal tissue, allowing the vet to determine whether there is a mass, cyst, tumor, abscess, fluid collection, or other abnormality.
Cytology
When diagnosing cat lymphomas, veterinarians use cytological (cell) analysis to examine cells taken from the cat’s body fluids. This test helps identify whether the cells are malignant (cancerous).
A veterinarian collects a fluid sample from the cat’s mouth, nose, throat, or abdomen to perform this test. Then, he smears the piece onto glass slides and examines them under a microscope.
If the cells appear abnormal, the vet may take another sample and repeat the process. He may also order additional tests, such as blood work, ultrasound imaging, biopsy, or surgery.
This test is most commonly used to diagnose lymphoma in cats. However, it can be used to detect any cancer.
Flow Cytometry
Flow cytometry is a diagnostic test to detect cancer cells in blood samples. Flow cytometry uses light scattering properties of particles suspended in the fluid to identify different types of cells.
Cancerous cells contain abnormal proteins called antigens that cause them to scatter light differently than normal cells. This difference in light scattering allows flow cytometers to distinguish between healthy and unhealthy cells.
Flow cytometry is often combined with immunohistochemistry (IHC) to confirm results. Immunohistochemistry involves staining tissue sections with antibodies specific to antigens found only in cancer cells. Then, the stained tissue is examined microscopically to determine whether any cancer cells are present.
Histopathology
Histopathology is the study of tissue samples taken during biopsies. The goal is to determine whether the cells are cancerous or benign (noncancerous). This helps vets decide whether treatment should be administered or not.
When performing histopathology, there are two main methods: frozen sectioning and paraffin embedding. Frozen sectioning involves taking small pieces of tissue and freezing them quickly. Then, the sample is sliced at -20 degrees Celsius (-4 degrees Fahrenheit) and examined under a microscope.
Paraffin embedding requires cutting the tissue into thin sections and placing them onto slides. Next, these slides are placed in a hot oven where the wax melts and hardens. Once hardened, the fall is stained and examined under a microscope for signs of cancer.
Treatment for Lymphoma in Felines
Cats with lymphoma often have a longer life expectancy if diagnosed early. This is because chemotherapy drugs kill off healthy and diseased cells, including those that cause tumors. With early detection, cats can live up to 10 years beyond what is considered normal for their breed. Here are the following treatments for cats with lymphoma.
Chemotherapy
Chemotherapy is the standard treatment for lymphomas. Depending on the type of lymphoma, chemotherapy can take several forms. Some patients receive infusions of drugs directly into the bloodstream, while others are given intravenous doses of medication. Others undergo radiation therapy. For many people, chemotherapy is followed by additional immunotherapy or stem cell transplantation treatments. About 50 to 70% of cats treated go remission as lymphoma responds to chemotherapy.
Radiation therapy
Radiation therapy is sometimes used to treat lymphomas. This involves placing radioactive material inside your cat’s body. Sometimes, it is used alone, but frequently it is combined with chemotherapy.
Palliative Care
Palliative care is often suggested if there is no chance of a cure. Patients with lymphoma may experience fatigue, pain, nausea, loss of appetite, difficulty breathing, and even bleeding. They may require hospitalization during treatment.
Multidrug Protocols
Multidrug protocols are commonly used in the initial stages of treatment. These involve combining different chemotherapy drugs to increase effectiveness against the tumor cells. However, factors may change the regimen to include newer medications if the disease progresses.
Prevention for Cat Lymphoma
A vaccine against the feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) can prevent the development of lymphoma. In addition, testing cats for both viruses can help detect early signs of infection. Here are the other things you can do to prevent lymphoma from developing in your cats.
- Be Aware of Environmental Toxins
Toxic substances can damage cats’ livers, kidneys, and central nervous systems. These poisonous substances include heavy metals, solvents, herbicides, insecticides, fungicides, and rodenticides.
Some familiar sources of exposure to these toxins include food, water, air, soil, plants, and household cleaning supplies. Make sure that your cat does not consume any of these items.
- Avoid Pesticides and Fertilizers
Pesticide residues and fertilizer runoff can contaminate the environment and enter waterways. As a result, these substances threaten the health of wildlife and humans.
Ensure you avoid using pesticide sprays or fertilizers near your house or yard. Instead, choose organic alternatives whenever possible.
- Monitor Your Cat’s
A protein-rich diet can promote the growth of lymphocytes, which are abnormal white blood cells that can become cancerous.
In addition, diets high in carbohydrates and fats can encourage the proliferation of tumor cells. Therefore, it is recommended that you feed your cat a balanced diet consisting of lean meats, vegetables, fruits, and grains.
- Check Your Pet’s Vaccination Records
Vaccines are practical tools used to prevent infectious diseases. However, vaccines can sometimes cause side effects, including fever, diarrhea, vomiting, and seizures.
You must monitor your cat’s vaccination records closely. Any signs of unusual behavior should prompt further investigation.
- Seek Medical Attention Early
Early diagnosis and treatment of lymphoma in cats can significantly improve the chances of survival. Contact your veterinarian immediately if your cat exhibits symptoms associated with lymphomas, such as coughing, sneezing, difficulty breathing, or swelling of the face, neck, or abdomen.
Frequently Asked Questions
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