How Many Lipomas Are Normal In Dogs?

What are Lipomas?

Lipomas are benign fatty tumors that develop under a dog’s skin. According to VCA Animal Hospitals, “A lipoma is a term to describe a very common benign tumor of fat seen in middle-aged to older animals.”1 Lipomas most often develop between a dog’s skin and muscle layer, usually on the torso, legs, or shoulder areas.

Lipomas are soft, movable lumps that feel doughy or rubbery to the touch. They are often covered with hair and can range from pea-sized to several inches wide. The overlying skin has a normal appearance. Lipomas are usually painless.2 Though benign, if they grow large enough, lipomas can impede movement or become bothersome.

How Common Are Lipomas in Dogs?

Lipomas are very common in dogs, with estimates that up to 2% of all dogs develop at least one lipoma. According to one study published in Veterinary Record, the median age of dogs diagnosed with a lipoma was 10 years old, much older than the median age of 4 years for non-lipoma dogs [1]. Another study reported that approximately 1 in 5 veterinary visits for lumps and bumps in dogs resulted in a lipoma diagnosis [2].

Certain breeds seem more prone to developing lipomas. Labrador Retrievers, Doberman Pinschers, Schnauzers, and mixed breed dogs show a higher incidence. Overweight and older dogs also tend to be more commonly affected.

What Causes Lipomas in Dogs?

The exact cause of lipomas in dogs is not fully understood, but research suggests there may be both genetic and lifestyle factors involved.

Some studies indicate there could be a hereditary component, as certain breeds like Labrador Retrievers, Doberman Pinschers, and Schnauzers appear more prone to developing lipomas. The tendency to form lipomas may be passed down genetically in these breeds. However, no specific genetic mutation has been identified as directly causing lipomas.

Obesity and high body fat also seem to play a role. Lipomas are made up of fat cells that proliferate abnormally. Obese dogs tend to have more proliferating fat cells, increasing the chances that some may form into lipoma lumps. One study found that overweight dogs had 3 times higher risk of developing lipomas compared to dogs fed a calorie-controlled diet. Reducing obesity may help lower lipoma risk.

While the exact mechanisms are still being studied, it appears that a complex interplay between genetic predisposition and lifestyle factors like diet and weight can influence lipoma development. However, lipomas can occasionally develop even in dogs that are not overweight or of a predisposed breed.

At What Age Do Lipomas Develop?

Lipomas typically develop in middle-aged to older dogs, with the average age of onset being between 6 to 10 years old. However, they can develop at any age.

According to a study published in the Veterinary Ireland Journal, the median age for dogs with lipomas was 10 years old, compared to 4 years old for dogs without lipomas.1 Another study found the mean age for dogs with lipomas was 8.6 years old.2

While lipomas are more common in senior dogs, they can occur at any age. Some sources report lipomas occurring in dogs as young as 2 years old. However, the risk increases significantly as dogs reach middle age and beyond.

As dogs continue to age, they are more prone to developing multiple lipomas rather than just one or two. Older dogs tend to get lipomas at an earlier age compared to younger dogs.

Where Are Lipomas Usually Located?

Lipomas can develop anywhere on a dog’s body where fat is located. However, there are some common areas where they tend to occur more frequently:

On the torso: Lipomas often form along the chest, back, flanks, and abdomen. These areas contain a significant amount of fat deposits underneath the skin.

Legs: The thighs and upper legs are other common sites for lipomas in dogs. They may form around the joints or along the length of the legs.

Head and neck: Some lipomas emerge on the head, neck, and shoulders. They may grow on the throat, behind the ears, or under the chin where loose skin is present.

Certain breeds are more prone to developing lipomas in particular locations. For example, Labrador Retrievers often get lipomas on their torsos, while Doberman Pinschers tend to grow them on their legs and hips [1].

Overall, areas with substantial fat deposits and loose skin see the highest occurrence of lipomas. Monitoring these common hotspots can help identify lipomas early.

What Are the Signs of a Lipoma?

The most common sign of a lipoma is the appearance of a soft, movable lump under the skin, which feels like a soft swollen area or bulge. Lipomas are usually round or oval-shaped lumps that move easily when touched. They have a rubbery or doughy texture and are not painful. Most lipomas do not cause any discomfort or pain for the dog.

According to the WebMD article on lipomas in dogs, “The most visible symptom of a lipoma is the formation of lumps or fatty tumors on dogs, which you can easily feel with your bare hands.” The lumps range in size from a marble to a golf ball and can grow anywhere on the body. However, they are most commonly found on the torso, upper legs, and shoulders.

Because lipomas are made up of fatty tissue, they have a soft, pliable feel when touched. The Denvervet.com article notes that “Lipomas are characterized as small, hemispherical lumps that can be felt just under your dog’s skin. The lump will likely feel somewhat soft and moveable if you apply pressure.” The texture helps differentiate lipomas from other kinds of lumps or tumors which may feel firmer or solid.

While the lipoma may grow larger over time, it usually does not inflame or become painful. Embracepetinsurance.com states that most lipomas “do not ever bother the dog, even as they slowly expand.” Monitoring the lipoma for any changes is advisable though, as a sudden increase in size or texture could indicate a problem.

When Should a Lipoma Be Removed?

Lipoma removal surgery is typically recommended if the lipoma:

  • Is rapidly growing or changing
  • Is impairing movement or mobility
  • Is ulcerated, irritated, or bleeding
  • Is compressing or infringing upon other structures
  • Is suspected to be malignant based on testing

Removal is also often advised for lipomas that are large, bothersome, or in high-friction locations. Cosmetic/appearance reasons may factor into some owners’ decisions as well.

The benefits of surgical removal include eliminating the mass and relieving any associated discomfort. Testing can also confirm benignity. Risks include those associated with anesthesia, infection, bleeding, swelling, and recurrence. While low, there is also a small risk that the lipoma is actually a form of fat cell cancer called liposarcoma. For uncomplicated lipomas, the likelihood of complications is very low in healthy dogs.

Overall, the risks of removal are usually low compared to the benefits of eliminating the lipoma. However, in older or sick dogs, surgical risks may outweigh benefits for benign lipomas that are not causing problems. Discussing options with a veterinarian is important.

What Are the Risks of Lipomas?

For the most part, lipomas in dogs pose minimal health risks on their own. Lipomas are benign tumors consisting of fat cells that typically grow slowly between the skin and muscle layer. Since they are usually moveable and soft, lipomas generally do not directly impact the health of dogs.

However, in some cases, lipomas can cause issues if they grow in size and press against internal organs. Large lipomas in the chest or abdomen can put pressure on organs like the lungs, liver, or intestines. This compression can make it difficult for the organs to function properly. Lipomas in these areas may require surgical removal.

Additionally, while rare, lipomas can transform into a form of cancer called liposarcoma. In this case, the fatty tumor develops into a malignant one made up of fat cells and fibrous tissue. However, the chances of this occurring are very low.

Overall, most lipomas are harmless growths that can be left alone without problem. But large or rapidly growing lipomas may require monitoring and removal in some cases, especially if impacting normal organ function. Consulting with a veterinarian can help assess any risks specific to your dog.

Source: https://vcahospitals.com/know-your-pet/adipose-lipoma-tumors

How Are Lipomas Diagnosed?

Lipomas are usually diagnosed through a physical exam by your veterinarian. Your vet will feel the lump to determine if it moves freely under the skin and feels soft and fat-like. This helps distinguish a lipoma from other kinds of lumps or tumors which may feel hard and fixed in place.

To confirm it is a lipoma, your vet may recommend a fine needle aspirate. This involves using a small needle to extract cells from the lump so they can be examined under a microscope. Fat cells will confirm that the lump is a benign lipoma rather than another type of mass. Imaging tests like x-rays or ultrasound may also be used to visualize the characteristics of the lump.

It’s important to have any new lumps or bumps on your dog evaluated, as some may require treatment. Getting an accurate diagnosis from your vet will ensure proper care. While most lipomas are harmless, your vet can determine if the lipoma is in a location that puts your dog at risk for impairment or irritation. Catching lipomas when they first develop allows for better management.

Source:
https://www.petmd.com/dog/conditions/skin/c_multi_lipoma

Preventing and Managing Lipomas

While there’s no sure way to prevent lipomas from developing, there are some steps dog owners can take to potentially reduce the risk and manage existing lipomas:

Weight Control and Diet: One of the most important factors is maintaining a healthy weight, as overweight and obese dogs are more prone to developing lipomas. Feeding a high-quality diet formulated for your dog’s size, age, and activity level can help keep the weight down. According to research on PetMD, diets rich in omega-3 fatty acids from fish oil may also help reduce inflammation and prevent obesity, which are risk factors for lipomas.

Monitoring Changes: Check your dog’s body regularly for any new lumps or bumps. Keep an eye on the location, texture, size, and any changes. Report any new lipomas to your veterinarian. Monitoring existing lipomas will help determine if and when surgical removal may become necessary.

Knowing When Removal is Needed: While many lipomas can be left alone, surgical removal may be recommended if the lump is impairing mobility, shows signs of ulceration or infection, or is rapidly growing in size. Your vet can best determine if and when a lipoma should be removed based on its effects on your dog’s health and quality of life.

While lipomas can’t always be prevented, keeping your dog at a healthy weight, feeding a nutritious diet, and monitoring for changes can help manage their risk and impact. Consult your veterinarian for advice on caring for your specific dog.

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