Expanding on the topic of tumors discussed last week, this blog is devoted to lipomas, aka fatty tumors. Of all the benign growths dogs develop as they age, lipomas are one of the most common. They arise from fat (lipid) cells and their favorite sites to set up housekeeping are in the subcutaneous tissue (just beneath the skin surface) of the axillary regions (armpits) and alongside the chest and abdomen. Every once in awhile lipomas develop internally within the chest or abdominal cavity. Rarely does a dog develop only one lipoma. They tend to grow in multiples and I’ve examined individual dogs with more lipomas than I could count.
Should lipomas be treated in some fashion? In the vast majority of cases, the answer is a definite, “No!” This is based on their benign, slow-growing nature. The only issue most create is purely cosmetic, which the dog could could care less about!
There are a few exceptions to the general recommendation to let sleeping lipomas lie. A fatty tumor is deserving of more attention in the following situations:
1. A lipoma is steadily growing in an area where it could ultimately interfere with mobility. The armpit is the classic spot where this happens. The emphasis here is on the phrase, “steadily growing.” Even in one of these critical areas there is no reason to surgically remove a lipoma that remains quiescent with no discernible growth.
2. Sudden growth and/or change in appearance of a fatty tumor (or any mass for that matter) warrant reassessment by a veterinarian to determine the best course of action.
3. 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/or treated with radiation therapy.
4. Occasionally a lipoma grows to truly mammoth proportions. If ever you’ve 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 tumors have the potential to cause the dog discomfort. They can also outgrow their blood supply, resulting in possible infection and drainage from the mass. The key is to catch on to the mass’s rapid growth so as to surgically remove it before it becomes enormous in size and far more difficult to remove.
How can one prevent canine lipomas from occurring? No one knows. Anecdotally speaking, it is thought that overweight dogs are more predisposed to developing fatty tumors. While I’m not so sure I buy this, I’m certainly in favor of keeping your dog at a healthy body weight.
Does your dog have any lipomas?
Nancy Kay D.V.M.
Diplomate, American College of Veterinary Internal Medicine
Author of Speaking for Spot: Be the Advocate Your Dog Needs to Live a Happy, Healthy, Longer Life
Author of Your Dog’s Best Health: A Dozen Reasonable Things to Expect From Your Vet
Spot’s Blog: http://www.speakingforspot.com/blog