A lipoma is a benign tumor made up of fat cells. They are soft, movable lumps that form under the skin, commonly occurring in middle-aged to older dogs. Lipomas are the most common skin tumors found in dogs. They can develop anywhere on the body where fat is deposited, but certain locations are more prevalent.
According to a 2018 study published in BMC Veterinary Research, the one-year prevalence of lipomas in dogs under primary veterinary care in the UK was 1.94%. The study analyzed over 500,000 dogs across 628 primary veterinary practices.
While lipomas can develop anywhere fat is stored under the skin, they tend to occur most often on the trunk and legs. Some of the most common locations for lipomas in dogs include the chest, abdomen, legs, and armpits.
Common Locations
Lipomas can occur anywhere on a dog’s body where fat is present. However, there are certain areas where they are most likely to develop. Some of the most common locations for lipomas in dogs include:
Chest
A dog’s chest and rib cage contain layers of fat to protect organs, so lipomas often form in this area. According to VCA Hospitals, chest lipomas may grow quite large before being detected since they have room to expand before causing discomfort[1].
Abdomen
Lipomas can also develop inside a dog’s abdomen around organs like the liver, spleen, and intestines. These internal lipomas may grow very large before being found. Thornton Vets notes fatty tumors in the abdomen tend to be more concerning as they can sometimes interfere with organ function[2].
Legs
A dog’s legs provide easy access to fatty tissue under the skin, so lipomas commonly grow on the front and back legs. WebMD mentions leg lipomas usually appear as small, soft lumps that slowly get larger over time[3].
Armpits
The armpit or axillary region contains many blood vessels and lymph nodes surrounded by fat. This area allows lipomas room to expand, though armpit lipomas tend to be noticed more quickly since they can limit limb motion.
[1] https://vcahospitals.com/know-your-pet/adipose-lipoma-tumors
[2] https://www.denvervet.com/site/blog/2022/08/31/fatty-tumor-lipoma-dog
[3] https://www.webmd.com/pets/dogs/what-to-know-lipoma-in-dogs
Chest Lipomas
The chest is one of the most common places for lipomas to develop in dogs. Lipomas on the chest frequently grow quite large due to the ample space and tissue in this area. According to [Source 1], “Huge lipomas on dogs chest [can occur]. Huge lipoma on dog’s chest.” Large lipomas on the chest can cause discomfort and mobility issues as they put pressure on muscles and nerves in the chest and front legs.
However, most chest lipomas in dogs remain small to moderate in size. Their presence alone does not necessarily require removal, but larger lipomas that impact movement or quality of life may need surgical extraction. As always, consult your veterinarian to determine the best course of treatment.
Abdominal Lipomas
The abdomen is a very common location for lipomas to occur in dogs. According to the Denver Vet [1], the abdomen, chest, and tummy are the most common locations for lipomas. Lipomas on the abdomen tend to be larger in size compared to other locations. This is because there is more space and fat deposits in the abdominal area for the lipomas to grow.
Abdominal lipomas can range in size from very small lumps to large masses over 10cm in diameter. Larger lipomas may impact organ function or mobility if they compress on internal organs, blood vessels, or nerves in the abdomen. However, most abdominal lipomas remain benign fatty tumors that do not cause any issues other than their outward appearance. It’s still recommended to have abdominal lipomas examined by a vet, especially rapidly growing ones, to rule out cancer.
Leg Lipomas
Lipomas on a dog’s legs most often occur on the front legs rather than the back legs. Front leg lipomas tend to form on the inside of the leg in the armpit region, while hind leg lipomas often occur on the rear thighs.1
Lipomas on the legs can grow quite large, with some reaching the size of a grapefruit. Large lipomas may become bothersome if they limit mobility or cause discomfort when the dog sits or lies down. Lipomas on the legs near joints can also impede range of motion if they compress or restrict joint movement.
While small leg lipomas may not cause issues, larger ones that impact movement or quality of life often require surgical removal. Therefore, it’s important to monitor leg lipomas and have them assessed if they appear to bothered the dog or restrict leg function.
Armpit Lipomas
Armpits are common locations for lipomas in dogs because the tissue in that area contains more adipose (fatty) tissue. The armpit region allows room for growth of these fatty masses without interfering with mobility as quickly as other locations may.1
Lipomas in the armpits often grow larger than other areas before becoming problematic. They may eventually cause discomfort when the dog lies on that side. Large lipomas can restrict range of motion of the front legs.2
Surgical removal is recommended if the lipoma becomes over 2 inches diameter. This prevents it from impairing mobility. Most dogs tolerate removal well and regain full function of the front legs afterwards.
Other Locations
While lipomas most commonly occur on a dog’s chest, abdomen, and legs, they can develop in other areas as well.1 Some other locations where lipomas may occur include:
Neck: Lipomas on the neck often develop in older dogs. They may start small but can enlarge over time, potentially affecting your dog’s mobility and range of motion if they impede the neck.
Back: Lipomas along the back and spine area tend to be soft and movable beneath the skin. monitor for any changes in size or texture, as some may press on the spinal cord.2
Tail: While less common, lipomas can occasionally form at the base of the tail. These may cause discomfort when sitting.
If you notice any new lipomas developing on your dog, especially in sensitive areas like the neck or tail, point them out to your veterinarian. Catching and treating lipomas early provides the best prognosis.
Diagnosis
The vet will start by doing a physical examination to feel for fatty tumors under the skin which are commonly soft and moveable. During the exam, your dog will be checked for signs of pain or discomfort when pressure is applied to the mass. If the tumor is in a location where it impairs movement or causes discomfort, the vet may recommend surgical removal.
Imaging tests like X-rays, ultrasound, CT scans or MRIs may be used to determine the extent of the tumor and whether it is affecting surrounding tissues. According to the FirstVet article on lipomas in dogs (https://firstvet.com/us/articles/lipomas-in-dogs), “Diagnostic imaging such as radiographs or ultrasound can help characterize lipomas. Well circumscribed fat density masses are highly suggestive of a benign lipoma.” These tests can help differentiate lipomas from other more serious tumors before surgical biopsy or removal.
Treatment
The treatment for lipomas depends on the size and location of the growth. Small lipomas that don’t cause discomfort often don’t require treatment beyond monitoring their size.
For lipomas that are growing quickly or affecting your dog’s mobility or quality of life, surgical removal is an option. Veterinarians can perform surgery to remove the lipoma and send it for biopsy to confirm it is benign fat cells and not cancerous.
According to Dr. Magda, the surgery is relatively straightforward. Most lipomas have a thin tissue capsule around the fatty tumor that makes them easy to remove. The surgery is done under general anesthesia and has a quick recovery time.
After surgical removal, the lipoma should not regrow in that location. However, some dogs may develop additional lipomas later on. Close monitoring and regular veterinary checkups are recommended to watch for any new growths.
Prevention
While it’s difficult to completely prevent lipomas from developing in dogs, there are some strategies that may help reduce the risk according to this source.
Regular exercise and maintaining a healthy weight can help prevent lipomas. Overweight and obese dogs tend to develop lipomas more frequently. Getting your dog adequate daily activity and keeping their weight within the normal range recommended for their breed can potentially lower their chances of developing lipomas.
Feeding your dog a nutritious, balanced diet may also help. Some research suggests that diets high in carbohydrates, hormones, and omega-6 fatty acids could contribute to lipoma development. Choosing a high-quality dog food designed for your dog’s life stage and activity level can provide balanced nutrition without excess calories.
While these preventative measures are not guaranteed to stop lipomas, they can support your dog’s overall health and may reduce risk factors associated with lipomas.
