Cutaneous Lymphoma in Cats

Cutaneous lymphoma is a rarely occurring cancer in cats. It exists in two categories, epitheliotropic (having to do with the cellular tissue lining cavities in the body) and non-epitheliotropic. Epitheliotropic cutaneous lymphoma is further broken down into three specific types of occurrences, mycosis fungoides (the most common), sezary syndrome, and pagetoid reticulosis. While all of the aforementioned variations of cutaneous lymphoma affect the skin, often the cancer is present in other locations, mainly the kidneys and nasal or mouth cavities. 

In the body of a cat, immune system cells called “lymphocytes” carry vital fluids through the blood and tissue. When these cells become cancerous, commonly referred to as neoplastic, the entire body may be affected. Some of these lymphocytes line the organs or mucous membranes of a cat, serving as protection against infections. When these cells becomes neoplastic, skin tumors and lesions can develop. Issues of the skin are called cutaneous in the medical community. Cancer of the lymphocytes is known as lymphoma. The combination of the two is a condition called cutaneous lymphoma.

While most symptoms involve the skin, many times internal body parts also exhibit signs of a problem. When any of these symptoms are present, a veterinary assessment is needed. Symptoms are as follows:

• Raised lumps under the skin
• Ulcerations
• Dry or hairless patches on the skin
• Scabs and crusting
• Peeling skin
• Swollen lymph nodes
• Loss of appetite
• Weight loss
• Vomiting
• Diarrhea
• Nasal discharge
• Nose bleeds
• Sneezing
• Labored breathing
• Depression 
• Lethargy
• Polyuria (frequent urination)
• Polydipsia (increased thirst)
• Weakness

The exact reason that lymphoma of any type develops in cats is unknown. Certain factors are suspected to have an influence on lymphocytes becoming neoplastic. Possible causes include:

• Presence of Feline Leukemia Virus (FeLV)
• Presence of Feline Immunodeficiency Virus (FIV)
• Tobacco smoke

Due to the decrease in both FeLV and FIV in cats because of vaccination, instances of cutaneous lymphoma have also dropped. Outdoor cats who are not vaccinated are at the most risk for contracting these viruses. 

Once you have brought your cat to a veterinary clinic or animal hospital, the veterinarian will require the cat’s full medical history. A physical examination will be completed to assess visible and obvious symptoms. Great care should be taken in diagnosing cutaneous lymphoma, as symptoms relating to the skin are easily misdiagnosed. 

A histopathological examination will be needed to microscopically evaluate affected cell tissue from the cat. This tissue can be collected from a biopsy or a fine needle aspiration. Once examined, lymphoma can be confirmed and the aggression of the cancer may be determined. 

Full blood work is necessary to monitor white blood cells in the bloodstream. This is done with a complete blood count and a serum chemistry panel. Urinalysis may be needed to test kidney function and assess whether the lymphoma is present there also. X-rays and ultrasounds can determine if any other tumors or abnormalities exist in the cat. Feline leukemia virus and feline immunodeficiency virus should be tested for as they are present in so many cutaneous lymphoma cases. A PCR Antigen Receptor Rearrangement (PARR) test may be used to differentiate this condition from other cancers and lymph node disorders.

Cutaneous lymphoma is generally not curable. Vigorous treatment may extend a cat's life, especially if the cancer has been identified early in its progression.

Chemotherapy 

The most common treatment for cutaneous lymphoma is chemotherapy. This includes a combination of medications administered over many weeks time. Medications such as lomustine, chlorambucil, doxorubicin, cyclophosphamide and prednisolone are often prescribed, among others. The medications may need to be modified if severe side effects occur.

Radiation Therapy 

This vigorous Monday to Friday treatment may be used if lymphoma is present in the nasal cavity.

Surgical Removal 

If large nodules or tumors are present on the skin's surface, surgical removal may be necessary. This can be risky, as the cat is already in a fragile state due to the presence of cutaneous lymphoma and its effect on the immune system. General anesthesia is used for this surgery, and antibiotics are often prescribed for two to four weeks upon discharge of the cat. 

Cutaneous lymphoma has no cure, but a cat’s life span may be increased by treatment. On average, the cat will only live six to twelve months after treatment before remission occurs. If the cat also has FeLV or FIV, prognosis may be more guarded. Euthanasia is often the next step to ensure the cat does not suffer. A small number of cats may live up to two years after treatment. 

The best way to avoid cutaneous lymphoma is to prevent your cat from coming into contact with FeLV and FIV. Vaccinating your cat and keeping it indoors greatly reduce the chance of exposure to these harmful viruses.