Dog Lipomas: These Dog Fatty Tumors are Big Softies
Veterinarian Dr. Nancy Kay on why these fatty tumors aren’t always cause for concern.
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Of all the benign growths your pup might develop as they age, lipomas (a.k.a. fatty tumors) are one of the most common. Older dogs often have at least one or two cutaneous (within the skin) or subcutaneous (just beneath the skin surface) lumps and bumps. They’re common by-products of the aging process. The good news is, most of these tumors are benign (not cancerous) and totally harmless. But there are a small number of malignant (cancerous) masses — which is why it’s important to have your veterinarian inspect any new lumps and bumps your dog develops.
Lipomas in dogs often give pet parents severe anxiety when there are multiple or very large masses present. So it’s a good idea to get to know what your dog’s healthy, normal body looks like by performing regular at-home physical exams. Generally, the smaller a cancerous growth is at the time of treatment, the better the outcome.
What Are Lipomas?
Lipomas are very common fat-based masses, or tumors, seen on middle-aged and senior dogs, and they’re generally benign. These soft, slightly moveable masses arise from fat, or lipid, cells and are typically found in the subcutaneous tissue of axillary regions. Pet parents often find these lumps in areas like the armpits and alongside the dog’s chest and abdomen — though occasionally lipomas develop within the chest or abdominal cavity.
Dogs rarely develop only one lipoma. They tend to grow in multiples, sometimes more than you can count. While lipomas usually grow slowly, each one is different and some progress much more quickly.
Fatty tumors that grow between the muscles are called infiltrative lipomas, and when malignant, they’re called infiltrative liposarcomas. There’s no way to determine what type of lipoma your pup has by feeling alone, but your veterinarian can determine if it’s problematic through a biopsy test called fine needle aspirate. After a sample is extracted, it can be examined under a microscope to diagnose the fatty tumor. In some cases, a CT scan may be required to get an accurate reading of the mass.
What Is the Treatment for Lipoma in Dogs?
Treatment is not generally required for the vast majority of dog lipoma cases—that’s because of their benign, slow-growing nature. Lipomas don’t go away on their own, but the only issue most create is purely cosmetic — and trust us, your dog couldn’t care less.
But, in some circumstances, it may be beneficial to remove the lipoma. While surgical lipoma removal is relatively common, it is still a surgical procedure with risks such as anesthesia related-complications and post-op infection.
Veterinary Removal Costs
If your veterinarian recommends that the lipoma be removed, or you elect to do so for cosmetic purposes, expect to pay between $200 and $500 per removal of each fatty tumor mass. For difficult-to-reach lumps, pet parents should be prepared for the lipoma removal cost to rise upwards of $1000/each if a specialist is required.
When To Seek Veterinary Care
Given that pups often have multiple lipomas, removal costs can add up quickly. So, how do you know if the cost of surgical removal is worth it? There are a few exceptions to the general recommendation to let sleeping lipomas lie. A fatty tumor may require removal and definitely deserves more veterinary attention in the following situations:
1. The location of a lipoma interferes with mobility.
If a lipoma is steadily growing in an area where it could ultimately cause problems with a dog's mobility, you might choose to remove it before it gets too large. The armpit is the classic spot where this happens. That being said, even in one of these critical areas, you’ll likely need to have the lipoma surgically removed only if it’s growing large.
2. The tumor grows suddenly and/or changes in appearance.
Notice either and you should have a vet check out your dog right away and recommend the best course of action.
3. The lipoma is actually an infiltrative liposarcoma.
Every once in a great while, a fatty tumor turns out to be an infiltrative liposarcoma rather than a lipoma. These are the malignant black sheep of the fatty tumor family. Your veterinarian will be suspicious of an infiltrative liposarcoma if the fine needle aspirate cytology reveals fat cells yet the tumor feels fixed to underlying tissues. (Lipomas are normally freely moveable.) Liposarcomas should be aggressively surgically removed and sometimes treated with radiation therapy.
4. The lipoma expands to truly mammoth proportions.
If you’ve ever looked at a dog and thought, “Wow, there’s a dog attached to that tumor!” chances are you were looking at a lipoma. Such massive growths have the potential to cause the dog discomfort. They can also outgrow their blood supply, resulting in possible infection and drainage from the tumor. The key is to surgically remove the tumor before it becomes enormous and far more difficult to remove.
What Causes Lipomas in Dogs?
No one knows what causes lipomas because risk factors include a complicated mix of environment, genetics, diet, and care. There’s no simple solution for preventing lipomas in dogs, but there are a few things to consider when assessing your dog’s risk factors.
Age has a big impact.
Your dog’s chance of getting lipomas increases as they age. Compared with dogs between three and six years old, senior dogs nine years and older are 17 times more likely to develop a lipoma.
Weight plays a role.
Studies show that overweight dogs are more predisposed to developing fatty tumors. Keeping your pup at a healthy body weight isn’t a cure-all, but it’s a good thing to strive for.
Any dog can develop a lipoma, but some breeds have a higher predisposition to lipomas, including Dobermann Pinschers, Weimaraners, Labrador Retrievers, Springer Spaniels, Beagles, German Pointers, and Miniature Schnauzers. Overall, pure-bred dogs are more likely to develop lipomas than mixed breeds.
Can Lipomas in Dogs be Prevented?
While lipomas can’t be prevented, they should be monitored. Be sure to note any unusual lumps or changes in existing lipomas and keep up with your dog’s annual veterinarian exams so they can assist with diagnosis and mitigating any concerns.
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Nancy Kay, DVM
Nancy Kay, DVM is a board-certified specialist in the American College of Veterinary Internal Medicine. She was a recipient of AAHA’s Animal Welfare and Humane Ethics Award and is the author of Speaking for Spot.