A lipoma is a benign (non-dangerous) tumour of fatty tissue. Lipomas are very common in dogs. They appear as a soft tissue swelling under the skin that can be as small as 10mm and as large as 40cm in diameter. They are essentially a big lump of fat.
This is a lipoma surgically removed from a dog. It had a very small blood supply and the fatty tissue was contained within a capsule.
How do you diagnose a lipoma?
A suspected lipoma can be investigated by performing a fine needle aspirate. This is when a small sample is taken from the mass and examined under the microscope.
Lipomas have a distinctive appearance of liquid droplets when examined under the microscope. It must always be remembered that only a very small sample of the mass is being examined on a fine needle aspirate. If the lump grows quickly, is painful or changes rapidly it may not be a lipoma, even if there has been a fine needle aspirate.
What should you do if your dog has a lipoma?
Some dogs will develop a small fatty lump that grows slowly and does not cause any problem. These lumps can be left as they are not causing a problem.
Generally once the fatty lump becomes large – greater than 5 cm in diameter – you should be discussing the pros and cons of surgery with your veterinarian. We commonly see lipomas that are in excess of 10cm in diameter. These large tumours are much more difficult to remove, have increased chance of complications after surgery and cause physical distress.
If your dog had been diagnosed with a lipoma and that lump grows quickly, is painful or changes rapidly it should be reassessed. Sometimes other more dangerous tumours will grow close to a lipoma making the diagnosis challenging.
Lipomas found in certain regions of the body can be more problematic. Lipomas in the armpit will often spread deeply and wrap around the nerves supplying the leg. These tumours are more difficult to completely remove with surgery.
What do I do if my dog has multiple lipomas?
Some dogs, particularly Labradors, are especially prone to developing lipomas. Often 30 or more tumours can be found. If these tumours are left to to slowly grow, with time these dogs will be covered with disfiguring lipomas as they age. We recommend to discuss with your veterinarian, the surgical removal of the lipomas. All the tumours might not be removed, but there will be many less tumours when your dog is very old and less likely to be a good candidate for surgery.
What does lipoma surgery look like?
Most lipomas are located under the skin and above the body muscle level. Sometimes they lie deep to a muscle. Surgery usually involves opening the skin and removing the fatty lump with a small margin. This leaves a large space that may then fill with fluid, creating a post-operative seroma. A variety of surgical techniques are used to avoid a seroma and encourage timely healing. It is very important the dogs are kept very quiet after lipoma surgery to decrease any swelling. External sutures are sometimes placed and will be inspected and removed approximately 10 days after surgery.
Can the fat just be sucked out?
Unfortunately it is not possible to just put a needle into the lipoma and suck out the fat.
What if I put my dog on a diet?
If your dog puts on weight the added fat in the system will encourage lipomas to grow.
If your dog loses weight then lipomas do not appear to shrink but will grow more slowly.
Should I be worried about my dog’s lipomas?
Small lipomas are generally nothing to worry about unless they are growing rapidly or change. Each time you consult with your veterinarian, it is best to quickly review the lipomas and discuss if surgery is indicated, or if you can leave the lumps and simply observe them.