Lipoma in Dogs

What Are Lipomas in Dogs?

If you are a pet parent, chances are you have heard of lipomas, or at least their common name, fatty tumors. They are extremely common growths that are most often found in the tissue layers below a dog’s skin.

Lipomas in dogs are benign, noncancerous tumors that grow from fat cells. They are more common in overweight dogs and are more likely to develop as a dog ages.

Labrador Retrievers, Doberman Pinchers, Miniature Schnauzers, Cocker Spaniels, Dachshunds, Golden Retrievers, and Weimaraners develop more than their fair share of lipomas, but any breed can develop them.

Symptoms of Lipomas in Dogs

The main symptom of a lipoma is a lump or mass that you can feel just underneath your dog’s skin. You can usually define the borders of a lipoma relatively easy, though their shape can vary from round to oval to somewhat irregular and more bulbous.

They usually feel somewhat “squishy,” or fluctuant, though they can be firmer in texture. They can be firmly stuck in place if they are adhered to the surrounding tissues, or you may be able to move them around to some degree.

Lipomas can be found in just about any spot on (or in) a dog, but most are found on the pet’s abdomen and chest. Many lipomas are also found on a dog’s legs, but no location is off limits, including the organs inside a dog’s body.

Lipomas in dogs might start small, but their growth knows no limits. When they grow so large that they become heavy or outgrow their blood supply, they present problems from pain to necrosis. They can also cause problems with a dog’s mobility depending upon their location.

How Vets Diagnose Dog Lipomas

Because lipomas in dogs can appear and feel similar to other dangerous and malignant tumors, it is essential to get an accurate diagnosis of the mass.

Your veterinarian may recommend a noninvasive test known as a fine-needle aspirate and cytology exam. This is a diagnostic procedure where a needle is inserted into the mass for a sampling of cells.

The veterinarian will then stain the cells on a microscope slide and examine them under the microscope. This is a quick and safe test.

Typically, lipomas have oily material and fat cells that are easy to identify under the microscope. Taking a biopsy with a larger tissue size is essential to confirm that the mass is a lipoma, as it allows for a much more comprehensive examination of the mass. 

Sometimes these fatty tumors turn out to be malignant lipomas (called liposarcomas), even though they look and feel like their benign counterparts.

Treatment for Lipomas in Dogs

It is important to have an accurate diagnosis and to know that the mass is indeed a lipoma, but at this point, most lipomas require only monitoring. There is usually no reason to treat lipomas, as they pose no threat to your pup unless they are uncomfortably large or in an awkward location.

The growth of most lipomas is slow, alleviating the pressure to make a hasty decision about surgical removal if you are on the fence. Lipomas that are larger or invasive into surrounding tissue may be appropriate candidates for surgical removal. More rapidly growing tumors may also be suitable for surgical removal.

A less common type of lipoma, named an infiltrative lipoma for its classic behavior of infiltrating nearby tissues, can make surgery more problematic, as delineating the borders can be challenging and recurrence is likely.

Recovery and Management of Dog Lipomas

If you and your veterinarian opt for a conservative approach of monitoring your dog’s lipoma versus surgical removal, pay careful attention to monitoring the size and growth rate of the lipoma.

Record the size at least every six months and document it with photos and measurements. You can take pictures with your cell phone to record these growths. Lipoma growth is gradual, and many lipomas have been known to sneak up in size until they are as big as a basketball or even larger.

Always look for changes in the size, shape, or firmness, and check the integrity of the skin covering it. If your dog becomes irritated by the lipoma, this is a reason to rethink having the mass surgically removed.  

Maintaining your dog at a proper weight (and instituting a weight-loss plan as needed) will usually help control the growth of lipomas and prevent future ones. Some lipomas will shrink with weight loss but not disappear altogether.

Overall, the outlook after the diagnosis of a lipoma is generally great and no cause for alarm.