Fatty lumps in cats

Fatty lumps, also known as lipomas, are uncommon in cats. They are a type of tumour, but most of the time they cause no problems. Always have any skin lumps on your cat checked by a vet.

Most fatty lumps grow slowly and cause no discomfort. However, many skin lumps in cats look similar, and other lumps can be dangerous. If a lipoma (fatty lump) is confirmed, sometimes this can be monitored. If it starts growing quickly or changing, surgery should not be delayed.

Overview

What are fatty lumps in cats?

A fatty lump starts when a fat cell starts multiplying without control. This happens most often right under the skin but can happen in the chest or abdomen as well.

Some fatty lumps can grow into the muscles, these are called infiltrative lipomas and are much more likely to cause discomfort or complications.

Most fatty lumps will barely increase in size from week to week. Some cats can develop several fatty lumps over time.

Rarely, a fatty lump can be cancerous; these are liposarcomas. These grow much faster and spread to other areas of the body.

Speak to a vet if your cat’s skin lump is changing quickly.

Symptoms

Symptoms of fatty lumps in cats

Soft, squishy lump under the skin. Can feel a bit firmer if the skin in the area is quite tight.
The lump usually moves with the surrounding skin. If not, it could be an infiltrative lipoma.
Most lipomas grow very slowly over weeks to months
There should be no pain or redness; if these are present, there is likely a complication or a different problem going on.

Risk

Cats at higher risk for fatty lumps

Older cats are at higher risk for developing fatty lumps, as with most types of tumours.
Siamese cats may be more likely to develop fatty lumps.

Diagnosis

Diagnosis of fatty lumps in cats

A lipoma can be suspected on examination and palpation, but to know for sure, tests are required. There are two main options:

Fine Needle Aspirate (FNA): This is usually simple to do, causes little discomfort, and will be able to diagnose most lipomas.
Biopsy: if the FNA is inconclusive, a biopsy may be done. This requires anaesthesia and surgery but is the most reliable way to know exactly what is going on.

In cases where the fatty lump is growing into the muscle or inside the body, it may be necessary to do more advanced tests like x-rays or a CT scan.

Vet treatment

Vet treatment of fatty lumps in cats

Because lipomas are uncommon in cats, unlike skin cancer, your vet may recommend surgery to remove any lump to be safe. This is usually fairly simple when the lump is superficial and small.
An infiltrative lipoma is more difficult to manage, especially if located between muscles. Surgery can still be done, but often the lump grows back. Radiation therapy at a specialist centre may be necessary in these cases.
Cancerous fatty lumps are also treated with surgery and radiation therapy.

Home treatment

Home treatment of fatty lumps in cats

Fatty lumps are not painful if there are no complications. Your vet may recommend monitoring the lump. It may be useful to measure the lump every few weeks, this is best done with callipers. Another good option is to take a photo of the lump, ideally including something of known size in the image for comparison. Other useful things to monitor are:

Texture
Shape
Consistency
Whether the lump moves with the skin
How the skin looks over and around the lump
Any signs of pain, such as licking or defending the area

Prevention

Prevention of fatty lumps in cats

Avoiding excess body fat is always better for health, but this doesn’t appear to affect fatty lumps in cats.

Please don’t hesitate to ask a vet or vet nurse if you would like help managing your pet’s weight.

When to worry

When to worry about a fatty lump in your cat

It’s best to have your vet test any skin lump on your cat. If this has been done and no treatment is recommended, speak to your vet again if you notice any of the following: