Home » Diseases » In cats » Lymphoma, Lymphosarcoma (cancer caused by blood cells, the lymphocytes)

Lymphoma, Lymphosarcoma (cancer caused by blood cells, the lymphocytes) in cats

Occurrence: common
Location of illness: General/Whole body

Author: Dr. med. vet. Gisa Löwe | Last modified: 17.02.2026

When to visit the vet?

Urgent see a veterinarian within 24 hours

If the condition worsens / symptoms persist, consult a veterinarian.

Definition

Lymphoma, also known as lymphosarcoma, is a malignantMalignant means “cancerous” and is used to describe tumors or neoplasms that grow invasively and have the ability to metastasize. Malignant tumors can cause serious health problems in dogs and cats. cancerCancer refers to the uncontrolled proliferation of cells that can lead to tumors or spread throughout the body. Various types of cancer occur in dogs and cats, ranging from skin cancer to lymphomas. that originates from the lymphocytesLymphocytes are a group of white blood cells crucial for the body’s adaptive immune response. There are different types, including B cells, T cells, and natural killer cells, each with specific functions in the immune system., a type of white blood cell. These cells are an essential component of a cat’s immune systemThe immune system is the body’s defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body..

The most important facts at a glance

Lymphoma in cats are cancers caused by the uncontrolled proliferation of lymphocytesLymphocytes are a group of white blood cells crucial for the body's adaptive immune response. There are different types, including B cells, T cells, and natural killer cells, each with specific functions in the immune system., specialized immune cellsImmune cells are specialized cells of the immune system that help to identify and fight pathogens and foreign substances. These include leukocytes such as lymphocytes (T cells and B cells), macrophages, and dendritic cells. of the body. This disease can affect various areas of the body, including lymph nodes, the gastrointestinalGastrointestinal refers to the gastrointestinal tract, a system that extends from the oral cavity to the anus and is responsible for the digestion of food and the absorption of nutrients. tract, and the chest area. The exact causes of lymphoma are not yet fully understood, but genetic factors, environmental factors, and infections with viruses such as FelineFeline refers to anything related to cats. The term is used to describe diseases, behaviors, or anatomical aspects that are specific to cats. Leukemia VirusA virus is a microscopic infectious particle that cannot reproduce on its own and must infect a host cell to produce new virus particles. Viruses can cause a variety of diseases in humans, animals, and plants. (FeLV) and FelineFeline refers to anything related to cats. The term is used to describe diseases, behaviors, or anatomical aspects that are specific to cats. Immunodeficiency VirusA virus is a microscopic infectious particle that cannot reproduce on its own and must infect a host cell to produce new virus particles. Viruses can cause a variety of diseases in humans, animals, and plants. (FIV) play a role. Symptoms include enlarged lymph nodes, RespiratoryRespiratory refers to breathing or the process of breathing. Respiratory diseases affect the respiratory tract and can impair the ability to breathe effectively. distress, Weight loss, and Vomiting, while diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. is made through clinical examination, laboratory tests, and biopsyA biopsy is a medical procedure in which a small amount of tissue is removed from the body to be examined under a microscope for signs of disease. Biopsies can help diagnose cancer and other conditions.. Treatment depends on the form and stage of the lymphoma and often includes chemotherapyChemotherapy refers to the treatment of diseases, especially cancer, with chemical substances or drugs. It aims to kill cancer cells or prevent their growth, but can also affect healthy cells., sometimes combined with surgery or radiotherapy. The prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop. varies greatly, depending on the stage of the disease and the cat’s overall health. Preventive measures include avoiding FeLV and FIV infections, a balanced diet, and regular veterinary visits. Research focuses on genetic factors, new therapeutic approaches, and the role of viruses in the development of lymphoma. Advances in diagnostics and the development of new treatment methods could lead to better treatment outcomes in the future.

Causes

LymphocytesLymphocytes are a group of white blood cells crucial for the body's adaptive immune response. There are different types, including B cells, T cells, and natural killer cells, each with specific functions in the immune system. are specialized cells formed in the lymph nodes, spleen, and other organs of the lymphatic system. They play a crucial role in fighting infections. In lymphoma, these cells multiply uncontrollably, which can lead to Tumors in various body areas.

The causes of lymphoma in cats are diverse and not yet fully understood. Genetic factors are believed to play a role, as do environmental factors and infections, particularly with the FelineFeline refers to anything related to cats. The term is used to describe diseases, behaviors, or anatomical aspects that are specific to cats. Leukemia VirusA virus is a microscopic infectious particle that cannot reproduce on its own and must infect a host cell to produce new virus particles. Viruses can cause a variety of diseases in humans, animals, and plants. (FeLV) and the FelineFeline refers to anything related to cats. The term is used to describe diseases, behaviors, or anatomical aspects that are specific to cats. Immunodeficiency Virus (FIV). These viruses weaken the immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body. and increase the risk of lymphoma development.

There are various forms of lymphoma in cats, classified by the primaryPrimary refers to the first or original cause of a disease or condition, as opposed to secondary causes or symptoms that develop from it. affected area, such as mediastinal lymphoma (in the chest area), alimentary lymphoma (in the gastrointestinalGastrointestinal refers to the gastrointestinal tract, a system that extends from the oral cavity to the anus and is responsible for the digestion of food and the absorption of nutrients. tract), and multicentric lymphoma (in multipleMultiple means manifold or repeated and is used to describe conditions or events that occur in multiple instances or at different locations. In veterinary medicine, this may indicate multiple lesions, tumors, or other pathological changes. lymph nodes). Each form can have different causes and risk factors.

Symptoms

Very common symptoms:

Common symptoms:

Rare symptoms:

The symptoms of lymphomas in cats can vary greatly depending on the area affected. General signs may include weight loss, loss of appetite, lethargy, and fever. However, these symptoms are non-specific and can occur with many other conditions.

In alimentary lymphoma, which affects the gastrointestinalGastrointestinal refers to the gastrointestinal tract, a system that extends from the oral cavity to the anus and is responsible for the digestion of food and the absorption of nutrients. tract, vomiting, diarrheaDiarrhea refers to the condition of frequent, watery bowel movements, which can be a sign of infections, digestive disorders, or other health problems., and abdominalThe term “abdominal” refers to anything that concerns the belly or the abdomen. It is an adjectival expression used to describe the location, symptoms, or conditions that occur in the abdominal area. pain can often be observed. Cats may also suffer from dehydrationDehydration occurs when the body loses more fluid than it takes in. This can lead to a number of problems, including headaches, Dizziness, and in extreme cases, renal failure or Cardiovascular collapse. and poor body condition.

A mediastinal lymphoma can cause respiratoryRespiratory refers to breathing or the process of breathing. Respiratory diseases affect the respiratory tract and can impair the ability to breathe effectively. distress, cough, and an accumulation of fluid in the chest cavity, leading to shortness of breath. This form is often observed in younger cats, especially those infected with FeLV.

Multicentric lymphomas often affect multipleMultiple means manifold or repeated and is used to describe conditions or events that occur in multiple instances or at different locations. In veterinary medicine, this may indicate multiple lesions, tumors, or other pathological changes. lymph nodes and can lead to swellings that are palpable. This form is less specific in its symptoms and can often only be detected in advanced stages.

Diagnosis

The diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. of lymphoma begins with a thorough clinical examination and a detailed medical historyThe medical history is the systematic collection of a patient's medical history through questioning. It includes information about previous illnesses, treatments, allergies, and lifestyle habits.. The veterinarian will look for Swelling of the lymph nodes, RespiratoryRespiratory refers to breathing or the process of breathing. Respiratory diseases affect the respiratory tract and can impair the ability to breathe effectively. distress, and other non-specific symptoms.

Laboratory tests are essential and usually include blood tests to detect signs of anemia, changes in white blood cells, or other abnormalities. An X-rayX-ray is an imaging technique that uses X-rays to create images of the inside of the body. It is often used to diagnose bone fractures, lung diseases, and other conditions. or ultrasoundUltrasound refers to sound waves that are above the hearing threshold of the human ear. In medicine, ultrasound is used for diagnostic imaging procedures to visualize internal organs, tissues, and blood flow. examination can be used to identify Tumors or fluid accumulations.

The definitive diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. is often made by a biopsy, in which a tissue sample of the affected area is taken and examined microscopically. This method allows for determining the type of cells and assessing the degree of malignancyMalignancy refers to the aggressiveness of a tumor, that is, its ability to grow invasively and metastasize. Malignant tumors can be life-threatening in dogs and cats and require specific treatment..

In some cases, immunohistochemistryImmunohistochemistry is a laboratory technique that uses antibodies to identify and localize specific antigens in tissue sections. This method is used in veterinary diagnostics to detect and characterize diseases at the cellular level in dogs and cats. or flow cytometry may be performed to characterize the type of lymphocytesLymphocytes are a group of white blood cells crucial for the body's adaptive immune response. There are different types, including B cells, T cells, and natural killer cells, each with specific functions in the immune system. and identify specific markers that can help distinguish between different types of lymphoma.

Therapy

The treatment of lymphoma in cats depends on the form and stage of the disease. ChemotherapyChemotherapy refers to the treatment of diseases, especially cancer, with chemical substances or drugs. It aims to kill cancer cells or prevent their growth, but can also affect healthy cells. is the most commonly used method and can be used alone or in combination with other treatments. The goal is to control tumor growth and improve quality of life.

For alimentary lymphomas, surgical removal of the affected intestinalIntestinal refers to the intestine, the part of the digestive tract that extends from the stomach to the anus. Intestinal diseases affect the small and/or large intestine. segment may be necessary, especially if the tumorA tumor is an abnormal growth of tissue that can be benign or malignant. Tumors can develop in any part of the body and affect various functions. causes obstructions. ChemotherapyChemotherapy refers to the treatment of diseases, especially cancer, with chemical substances or drugs. It aims to kill cancer cells or prevent their growth, but can also affect healthy cells. is often used after surgery to destroy remaining cancerCancer refers to the uncontrolled proliferation of cells that can lead to tumors or spread throughout the body. Various types of cancer occur in dogs and cats, ranging from skin cancer to lymphomas. cells.

Radiation therapyRadiation therapy is the use of radiation, most often to treat cancer. It can be used to kill cancer cells or slow their growth without significantly damaging surrounding healthy tissue. can be used for localized lymphomas, especially if the tumor is located in an area where surgery is difficult. However, this method is less commonly applied in cats.

PalliativePalliative refers to treatments that aim to alleviate the symptoms of a disease without curing the disease itself. Palliative care focuses on improving the quality of life of patients with incurable diseases. treatments aimed at alleviating symptoms can also be part of the management, especially in advanced cases. These include pain relievers and anti-inflammatory medications.

Prognosis and follow-up care

The prognosis for cats with lymphoma varies considerably and depends on several factors, including the stage of the cancerCancer refers to the uncontrolled proliferation of cells that can lead to tumors or spread throughout the body. Various types of cancer occur in dogs and cats, ranging from skin cancer to lymphomas., the affected organs, and the cat’s general health. Early diagnosis and treatment can improve the prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop..

Cats with alimentary lymphomas generally have a better prognosis, especially if the cancer is confined to the intestineThe intestine is the medical term for the gut, including the small intestine (intestinum tenue) and the large intestine (intestinum crassum). It plays a central role in the digestion and absorption of nutrients. and can be surgically removed. Mediastinal lymphomas often have a poorer prognosisThe prognosis is the prediction of the likely course and outcome of a disease based on the general state of health, the nature of the disease, and the response to treatment. It can provide information on how a disease is expected to develop., particularly when associated with FeLV.

The average survival time of cats that respond to treatment is between a few months and several years. Long-term remission is possible, but relapse is common.

Prevention

The preventionPrevention includes measures taken to prevent diseases or injuries. In veterinary medicine, this includes vaccinations, parasite control, and health monitoring. of lymphoma in cats is a challenge, as the exact causes are often unknown. Nevertheless, there are some measures that may reduce the risk. One of the most important measures is avoiding infections with the FelineFeline refers to anything related to cats. The term is used to describe diseases, behaviors, or anatomical aspects that are specific to cats. Leukemia VirusA virus is a microscopic infectious particle that cannot reproduce on its own and must infect a host cell to produce new virus particles. Viruses can cause a variety of diseases in humans, animals, and plants. (FeLV) and the FelineFeline refers to anything related to cats. The term is used to describe diseases, behaviors, or anatomical aspects that are specific to cats. Immunodeficiency VirusA virus is a microscopic infectious particle that cannot reproduce on its own and must infect a host cell to produce new virus particles. Viruses can cause a variety of diseases in humans, animals, and plants. (FIV), as these viral infections can increase the risk of lymphoma development. Regular tests and vaccinations against FeLV can help minimize the risk.

A healthy and balanced diet can also contribute to the cat’s overall health and potentially strengthen the immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body.. Ensure your cat receives high-quality food and avoid Overweight, as ObesityObesity is the medical term for severe overweight, characterized by an excessive accumulation of fat in the body. It is often defined by a body condition score that is above the ideal range. can increase the risk of various diseases.

Regular veterinary visits are crucial to monitor your cat’s health and detect early signs of disease. Early detection and treatment of health problems can reduce the risk of developing more serious conditions.

Finally, it is advisable to minimize stressStress refers to the state of an organism reacting to external stimuli or demands. In veterinary medicine, stress can have physical or psychological effects on animals, impacting their health and well-being. for your cat, as stressStress refers to the state of an organism reacting to external stimuli or demands. In veterinary medicine, stress can have physical or psychological effects on animals, impacting their health and well-being. can weaken the immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body.. A calm and safe home, along with sufficient play and activity opportunities, can help promote your cat’s well-being.

Outlook on current research

Research into lymphoma in cats currently focuses on various aspects, including the genetic and environmental factors that contribute to the development of this disease. Scientists are investigating the specific genetic mutations that can lead to an increased risk of lymphoma in cats. A better understanding of these genetic factors could lead to more targeted diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. and treatment strategies in the future.

Another important area of research is the development of new therapeutic approaches. Work is currently underway to improve chemotherapyChemotherapy refers to the treatment of diseases, especially cancer, with chemical substances or drugs. It aims to kill cancer cells or prevent their growth, but can also affect healthy cells. protocols to minimize side effects and maximize effectiveness. Furthermore, there are promising studies on immunotherapies designed to stimulate the cat’s immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body. to specifically fight cancerCancer refers to the uncontrolled proliferation of cells that can lead to tumors or spread throughout the body. Various types of cancer occur in dogs and cats, ranging from skin cancer to lymphomas. cells. These approaches could lead to gentler and more effective treatment in the long term.

The role of viruses, particularly the FelineFeline refers to anything related to cats. The term is used to describe diseases, behaviors, or anatomical aspects that are specific to cats. Leukemia VirusA virus is a microscopic infectious particle that cannot reproduce on its own and must infect a host cell to produce new virus particles. Viruses can cause a variety of diseases in humans, animals, and plants. (FeLV) and the FelineFeline refers to anything related to cats. The term is used to describe diseases, behaviors, or anatomical aspects that are specific to cats. Immunodeficiency VirusA virus is a microscopic infectious particle that cannot reproduce on its own and must infect a host cell to produce new virus particles. Viruses can cause a variety of diseases in humans, animals, and plants. (FIV), is also being intensively researched. It is known that these viruses can increase the risk of lymphoma development, and researchers are working to better understand the mechanisms by which these viruses contribute to cancerCancer refers to the uncontrolled proliferation of cells that can lead to tumors or spread throughout the body. Various types of cancer occur in dogs and cats, ranging from skin cancer to lymphomas. development. In the long term, vaccinationVaccination is the process of administering a vaccine to develop immunity against a specific infectious disease. It is one of the most effective methods of prevention of infectious diseases. strategies against these viruses could help reduce the risk of lymphoma.

In addition, there are studies on environmental triggers that may contribute to the development of lymphoma in cats. These include factors such as passive smoking, certain pesticidesPesticides are chemical or biological substances used to control pests, including insects, weeds, and fungi. In dogs and cats, exposure to certain pesticides can be harmful to health and lead to signs of poisoning., and other environmental toxins. These studies aim to develop preventive measures that can reduce the risk of the disease.

In clinical research, new diagnostic tests are being developed to detect lymphomas earlier and more accurately. The use of biomarkers that can be detected in the cat’s blood or tissue is being intensively researched. These tests could help to detect the disease in a stage where it is still more treatable in the future.

Frequently asked questions (FAQs)

What is lymphoma in cats? Lymphoma is a type of cancerCancer refers to the uncontrolled proliferation of cells that can lead to tumors or spread throughout the body. Various types of cancer occur in dogs and cats, ranging from skin cancer to lymphomas. that affects the lymphatic system, which is part of a cat’s immune systemThe immune system is the body's defense system against infectious agents such as bacteria, viruses, fungi, and parasites. It comprises a complex network of organs, cells, and molecules that work together to protect the body.. It is one of the most common cancers in cats and can occur in various forms, depending on which lymphocytesLymphocytes are a group of white blood cells crucial for the body's adaptive immune response. There are different types, including B cells, T cells, and natural killer cells, each with specific functions in the immune system. or areas of the body are affected.
What are the symptoms of lymphoma in cats? The symptoms can vary depending on the affected area of the body. Common signs include loss of appetite, weight loss, lethargy, vomiting, diarrheaDiarrhea refers to the condition of frequent, watery bowel movements, which can be a sign of infections, digestive disorders, or other health problems., respiratoryRespiratory refers to breathing or the process of breathing. Respiratory diseases affect the respiratory tract and can impair the ability to breathe effectively. distress, or swollen lymph nodes. A veterinarian should be consulted if lymphoma is suspected.
How is lymphoma diagnosed in cats? DiagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. is made through a combination of clinical examination, blood tests, X-rayX-ray is an imaging technique that uses X-rays to create images of the inside of the body. It is often used to diagnose bone fractures, lung diseases, and other conditions. or ultrasoundUltrasound refers to sound waves that are above the hearing threshold of the human ear. In medicine, ultrasound is used for diagnostic imaging procedures to visualize internal organs, tissues, and blood flow. examinations, and a biopsyA biopsy is a medical procedure in which a small amount of tissue is removed from the body to be examined under a microscope for signs of disease. Biopsies can help diagnose cancer and other conditions. of the affected lymph nodes or organs. An accurate diagnosisA diagnosis is the identification of a disease or condition by its symptoms and/or results from diagnostic tests. It is the first step in the management and treatment of patients. is crucial for choosing the right treatment.
What treatment options are available for cats with lymphoma? The main treatment usually consists of chemotherapyChemotherapy refers to the treatment of diseases, especially cancer, with chemical substances or drugs. It aims to kill cancer cells or prevent their growth, but can also affect healthy cells., which aims to destroy cancerCancer refers to the uncontrolled proliferation of cells that can lead to tumors or spread throughout the body. Various types of cancer occur in dogs and cats, ranging from skin cancer to lymphomas. cells or slow their growth. In some cases, radiation therapyRadiation therapy is the use of radiation, most often to treat cancer. It can be used to kill cancer cells or slow their growth without significantly damaging surrounding healthy tissue. or surgical removal may also be necessary. The treatment is tailored individually to the cat.
Can lymphomas be cured in cats? The chances of a cure depend on the type and stage of the lymphoma. Some cats can go into remission with treatment, meaning that the disease is no longer detectable. However, a complete cure is rare, and the disease may recur.
How long can cats with lymphoma live? Life expectancy varies greatly and depends on the aggressiveness of the lymphoma, the cat’s general health, and the effectiveness of the treatment. Some cats can live for several months to years, especially if they respond well to treatment.
Are there risk factors for developing lymphoma in cats? Yes, risk factors include infectionAn infection is the colonization and multiplication of pathogens such as bacteria, viruses, fungi, or parasites in an organism, which often, but not always, leads to a disease. with the FelineFeline refers to anything related to cats. The term is used to describe diseases, behaviors, or anatomical aspects that are specific to cats. Leukemia VirusA virus is a microscopic infectious particle that cannot reproduce on its own and must infect a host cell to produce new virus particles. Viruses can cause a variety of diseases in humans, animals, and plants. (FeLV) or the FelineFeline refers to anything related to cats. The term is used to describe diseases, behaviors, or anatomical aspects that are specific to cats. Immunodeficiency VirusA virus is a microscopic infectious particle that cannot reproduce on its own and must infect a host cell to produce new virus particles. Viruses can cause a variety of diseases in humans, animals, and plants. (FIV), passive smoking, and possibly certain environmental toxins. Genetic factors could also play a role.
Can I take preventive measures against lymphoma in my cat? Some risk factors can potentially be reduced through vaccinations against FeLV and FIV, as well as by avoiding passive smoking and environmental toxins. A healthy diet and regular veterinary check-ups can also help maintain your cat’s health.
How is the quality of life of a cat with lymphoma ensured during treatment? Quality of life is ensured through close veterinary care, which aims to minimize treatment side effects and alleviate disease symptoms. A balanced diet and plenty of rest are also important.
Can alternative therapies help in the treatment of lymphoma in cats? While some alternative therapies, such as acupuncture or herbal supplements, can be used as an adjunct to conventional treatment, they should never serve as a substitute for veterinarian-recommended treatment. It is important to always discuss such options with a veterinarian.