What is Lipoma in dogs
A lipoma is a term to describe a very common benign tumour of fatty tissue, usually seen in middle-aged to older animals. These tumours can vary in terms of their rate of growth (some may remain the same size for years) but become problematic for your pet when they grow in locations that impact their ability to walk or cause discomfort. Lipomas can grow anywhere (even inside the abdomen), but the most common area is under the skin, where fat is normally present.
What causes lipomas in dogs?
There is no specific cause for lipoma in dogs. It is believed that lipoma, as well as some cancers, are caused by different environmental and genetic factors.
Written by Dr. Mariella Roberts, Veterinary Surgeon, Animal Trust Vets CIC | Published April 2025 | Review date April 2027 | This advice is for UK pets only and is not a replacement for seeing a vet
Symptoms
The most visible symptom of a lipoma is the formation of lumps or fatty tumours on dogs, under the skin, which you can easily feel with your bare hands.
The shape and texture of a lipoma can vary from dog to dog. Some lipomas are round or oval, while the others can be irregular or more bulging. They can feel either "squishy" or "firm" in texture.
Lipomas in dogs might start small, but they can have the potential to grow very large. When they grow so large that they become heavy or outgrow their blood supply, they present problems from pain to necrosis (death of the fatty cells due to loss of blood supply), or cause restriction of movement.
When to contact your vet
If you discover any form of lump or bump on your dog then it is best to have the lump examined by your vet. While your dog's lump may be a harmless lipoma, if the lump does turn out to be a form of cancer early detection and treatment are essential for good treatment outcomes.
Diagnosis
Typically, these types of tumours can be diagnosed by fine needle aspiration (FNA). FNA involves suctioning a sample of cells directly from the tumour, using a small needle, and placing them on a microscope slide for examination. In many dogs, this procedure can be performed conscious and during a consultation (although this may depend on the location of the mass and the temperament of your pet).
In some cases, results from FNA testing may not be entirely clear and a biopsy may be necessary. A biopsy is the surgical removal of a piece of the tumour. Pieces of the tumour are then examined by the lab under the microscope (histopathology). In many cases this testing is performed after surgical removal of the entire tumour.
Dog lipoma treatment
The single most effective treatment for lipomas is surgical removal. It is best to remove these masses when they are small; the surgery is usually less invasive, and the incision will be much smaller and less painful for your pet. As lipomas continue to grow, the surgery may become more difficult for both your vet and your pet.
A less common type of lipoma, named an infiltrative lipoma for its behaviour of infiltrating nearby tissues, can make surgery more problematic, as delineating the borders can be challenging and recurrence is more likely.
Very rarely, malignant forms of fatty tumours can occur (liposarcoma), although these are fortunately rare and do not develop by transformation of lipomas.
Prevention
A healthier diet, alongside exercise, may be one of the keys to preventing their development in the first place. Try to maintain pets at a healthy weight and body condition. Some lipomas will shrink with weight loss but not disappear altogether.
Outlook
Overall, the outlook after the diagnosis of a lipoma is good and most are no cause for alarm.
It’s a good idea to get your dog’s lumps checked regularly, however, even if they were diagnosed as lipoma, to make sure they’re not hindering your dog’s daily activities.