Fatty Tissue Tumor in Cats

Fatty tissue tumors are defined as infiltrative or non-infiltrative. Non-infiltrative tumors remain only within fatty tissue. Infiltrative fatty tissue tumors can spread into connective tissue or muscle. They are usually not so well-defined as non-infiltrative tumors.

Fatty tissue tumors are called lipomas. They are typically benign, made of fat and grow slowly. They feel like soft, round masses below the skin, and can occur as single or multiple tumors. 

A lump on the smooth surface of the cat's skin is the most common symptom. The bump can be oval or rounded with a slight definition. The animal may not show any signs of discomfort, and the tumors are often found on the abdominal area.

There are multiple causes of skin masses in cats, so it is necessary to determine the underlying origin of the tumor. 

Common causes of fatty tissue tumor include:

• Hormonal changes
• Sun exposure
• Aging
• Viruses
• Chemical exposure
• Obesity

Even though most fatty tissue tumors are benign, a lipoma should always be biopsied. This is because other tumors, such as infiltrative lipoma, a more invasive tumor, may feel like a benign, fatty lump to the touch. A lipoma biopsy is made by inserting a thin needle into the tumor and aspirating a tiny sample of the tissue. The tissue is placed under a microscope to determine whether the sample is benign or malignant. The vet may perform a complete blood count, a chemical blood profile, an electrolyte panel and a urinalysis. The blood and urine analysis plus biopsy will predict treatment options.

Lipomas in fatty tissue often grow slowly. Some pet owners may opt not to do anything about the tumor if it is not large or bothersome. Sometimes the tumor will continue to grow and become troublesome because it may infiltrate other bodily structures and impede normal function. Even if fatty tissue tumors are benign, a veterinarian may suggest removal, because they are rare in cats and are not easily distinguished from infiltrative lipomas.

The pet must be given no food or water in preparation for the surgery. The surgeon will need to record what medications the animal is currently receiving. The cat will be given a sedative right before the surgery, intravenous medications, and anesthesia. The surgical site will be shaved. The surgeon will remove the fatty tissue of the tumor and some of the tissue around it to ensure the most beneficial outcome.

If a hollow place is left where the tumor originated, a drain may be placed to prevent fluid buildup in the space. 

When the surgery is completed the cat will be given medications to relieve pain. These will be a combination of anti-inflammatory anesthetics and narcotics. Fluids will be administered intravenously to promote proper hydration. 

If a more invasive surgery was performed for a larger tumor, the pet may be required to spend the night in the hospital to make sure pain is controlled.

It is rare for a simple lipoma to recur after surgical removal, but it does occur. Infiltrative lipoma is infrequently found in cats, but requires very aggressive removal. They are found within muscle groups and can return. Sometimes followup treatment with radiation will be recommended for infiltrative lipoma. Another variant of infiltrative lipoma may be cancerous and is caused by feline leukemia viral infection. These tumors are also capable of returning, so follow-up radiation treatment is necessary.

At home, the cat should be monitored and the surgery site checked for infection. A collar can be placed around the animal's neck to prevent interference with the surgical site. If this is not done, the cat may open the sutures and cause an infection. Licking will impede the healing process because of bacteria transferred from the mouth.

The animal should be restricted from much exercise for three or four weeks after the surgery is performed. This may mean that food, water and litter box must be placed in an easily accessible area for recovery time.

Cats may not have much appetite after surgery, and refusing food for the first day or two after surgery is normal. Stomach upset after surgery may cause vomiting, as well. Make sure that plenty of water is available. If appetite continues to be low, smelly, canned foods may perk interest. Strained meats for babies can be inviting, also. If the cat still refuses to eat, a small amount of strained food administered into the mouth with a syringe may be effective. The food may be warmed a bit in a microwave to enhance the smell, but make sure it is not too hot. Petting and stroking may also stimulate the appetite.

If the cat attempts to hide or cries in pain, consult the vet for remedy. Do not give over-the-counter medications like acetaminophen to a cat, as these OTC medications are quite toxic to cats.

Completing follow-up visits to the veterinarian is very important after a surgical procedure to monitor healing and general health.