Key takeaways
Lymphoma is a cancer of the lymphatic system, which is involved in moving byproducts of the immune system throughout the entire body.
- Lymphoma can be present anywhere in the body and is categorized into four subtypes; multicentric, intestinal, mediastinal, and cutaneous
- Symptoms vary depending on the classification, stage, and location of the cancer but broadly include weight loss, loss of appetite, swelling of the lower abdomen, and swollen lymph nodes
- Diagnosis involves diagnostic imaging, blood work, cytology, and biopsy of the tumor
- Treatment can include surgery, chemotherapy, radiation therapy, hormone therapy, and palliative care
- The prognosis for lymphoma in horses is generally poor and the life expectancy after diagnosis is rarely over 6 months
- Cutaneous lymphoma has a better prognosis than the other subtypes, as it is less likely to metastasize, and is more receptive to surgical intervention
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A closer look: Lymphoma in Horses
Lymphoma in horses can be categorized into four categories which have specific symptoms.
Multicentric lymphoma occurs throughout the body, affecting multiple organs.
Intestinal lymphoma is localized to the intestinal tract.
Mediastinal lymphoma occurs within the chest.
Cutaneous lymphoma is found on the skin or under the skin (subcutaneous).
Risk factors
Lymphoma is the most common lymphatic cancer in horses, however, cancer is generally rare in horses. Lymphoma is prone to metastasis and has a very poor prognosis in the majority of cases.
Lymphoma is more likely to occur in horses over 5 years of age.
Possible causes
The cause of lymphoma is not known. Infections with viruses such as equine herpesvirus may predispose to developing lymphoma in rare cases.
Main symptoms
The symptoms of lymphoma can vary depending on the initial location of the tumor and whether the tumor has spread.
Testing and diagnosis
After a physical examination and medical history a number of diagnostic tests can be performed, including
- Diagnostic imaging, such as ultrasound to identify masses in the internal organs
- Bloodwork
- Cytology
- Biopsy
- Rectal palpation
- Endoscopy
Steps to Recovery
After a diagnosis of lymphoma, treatment depends on the location, subtype, and how far the tumor has spread. Treatments can include:
- Surgical removal of masses
- Chemotherapy
- Radiation therapy
- Hormonal therapy
- Palliative care with pain management
The prognosis for horses with lymphoma is poor, with the average survival time being around 4 months after diagnosis. In cases of cutaneous lymphoma, prognosis is fair, as it is less likely to metastasize and is easier to access for surgical removal.
Prevention
There are currently no known methods of prevention or risk reduction for lymphoma in horses. Staying up to date with regular veterinary appointments and vaccination schedules provides the best chance of early detection and maximizing health outcomes. Lymphoma is not contagious.
Is Lymphoma in Horses common?
Lymphoma is uncommon in horses.
Typical Treatment
- Surgery
- Chemotherapy
- Hormone therapy
- Palliative care
- Symptom/pain management
