What is That? Lipomas
By: Dr. Amanda Landis-Hanna
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I am often asked to check lumps and bumps…it is part of being a veterinarian. Sometimes they are due to infection, or may even be cancerous. Far and away, the most common lump is a lipoma. So what is that?
Lipomas are areas of fatty growth. They can grow in any location, but are most noticeable when they are just under the skin, in the subcutaneous fat. Because dogs’ skin is more loosely attached to the subcutaneous fat, it may allow lumps and swellings to emerge and be more easily felt. This looseness is in contrast to a human, whose skin is closely adhered to the subcutaneous fat.
Lipomas are fatty growths. In essence, it is a tumor composed of fat. They are usually benign, meaning they do not metastasize or spread to other tissues. That said, even benign growths may be harmful. If the growth is over a joint, or deeper into the body, it can cause problems. Fatty growths can alter blood flowing into an area, or how a joint is able to move. Lipomas inside the ribs can put pressure on the lungs.
Lipomas are more common in some breeds of dogs, such as Labrador Retrievers, Golden Retrievers, and some mixed breed dogs. They are also more common in older dogs, usually over 5 years old. Obese and overweight dogs are at much higher risk, due to the abundance of fat. The more fat a dog has, the more likely it is that some fatty cells may grow irregularly, causing a lipoma.
Lipomas may come in all shapes and sizes. Some are firm, while others are soft. A common problem veterinarians run into is a “suspect” lipoma. This term refers to a lump that the veterinarian believes is a lipoma, but a veterinarian cannot confirm a diagnosis without testing it. To diagnose a lipoma, veterinarians perform an aspirate or a biopsy.
An aspirate is when a small needle is stuck into the lump, and a few cells are sucked out. These cells are examined under a microscope, to ensure they are fat cells. The veterinarian also makes sure no signs of infection or cancer are seen.
A biopsy is slightly more invasive. Biopsies may be performed with general anesthesia or local anesthesia. Biopsies may be needed if an aspirate is inconclusive. A biopsy may also be needed if cells other than fat are seen; these results may mean that more than 1 cell type, or a mixed type of tumor may be present.
Once a diagnosis is made, your veterinarian will work with you regarding treatment. Surgery is the most common type of treatment, when treatment is necessary. My dog, Gus, developed a large, oval lipoma under one of his shoulder muscles. Due to the location, it impacted his ability to walk with his left shoulder, so I had to surgically remove it. Sophie, on the other hand, currently has many lipomas…10 at last count. None of these are impacting her quality of life, so we will continue to monitor them, without planning surgery (at this time).
Not all lipomas require surgery. Most lipomas are primarily cosmetic, meaning they do not cause a problem for your dog, other than in appearance. Some large lipomas, especially on the chest or abdomen, may need to be removed if it is uncomfortable for your dog to lie on it. Lipomas over the joints may need to be removed to prevent pain when moving.
The most important thing to remember is to get all lumps checked. You can make a note of the lump in your Voyce Notes, and take measurements with a measuring tape (to check for additional growth). If your veterinarian gives your dog a diagnosis of a lipoma, know that it is generally good news. You may need to address underlying issues, such as obesity, and surgery may be in your dog’s future. But remember, whatever the lump, open and clear communication with your veterinarian is key.