Sarcoma In Dogs: Everything You Need To Know

Medically reviewed by Nicole Wanner, DVM

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Soft tissue sarcomas make up 9 – 15% of all skin and subcutaneous (under the skin) tumors in dogs. Fortunately, it's unlikely that your dog will end up with one; only about 35-120 of every 100,000 dogs do.


Soft tissue sarcomas are a broad category of cancerous tumor that develops in the skin and connective tissues beneath it. These tumors can arise almost anywhere in a dog’s body; they might appear as a lump or be hidden from view internally.

Sarcomas in dogs are either low, intermediate, or high grade. These cancerous tumors can spread to surrounding tissue, and in rare cases, organs. Luckily, most sarcomas are low or intermediate grade, meaning that they are unlikely to spread.


There are over 70 types of sarcoma in dogs; these are some of the most common:

  • Spindle Cell Sarcoma In Dogs - The cells in a spindle cell sarcoma appear spindle-shaped when viewed under a microscope.
  • Histiocytic Sarcoma In Dogs - Histiocytic sarcomas appear in the histiocytic cells (immune cells) and usually occur in older dogs. They primarily appear in the legs and have a moderate to high chance of spreading. Any breed can get a histiocytic sarcoma, but Rottweilers, Bernese mountain dogs, and flat-coated retrievers are more likely to get these tumors.
  • Fibrous Sarcoma In Dogs/ Fibrosarcoma In Dogs - Fibrous Sarcoma originates in the fibroblast cells (a standard connective tissue cell in dogs), usually the limbs and mouth. Large breeds are more likely to develop a fibrosarcoma.
  • Synovial Sarcoma In Dogs - Synovial sarcomas develop in the lining of the joints; they have a moderate to high chance of spreading to the lymph nodes or lungs.
  • Hemangiosarcoma in Dogs - Hemangiosarcoma develops in a dog's blood vessels, which gives them a relatively high chance of spreading. Hemangiosarcoma often originates in the spleen and is sometimes referred to as a splenic sarcoma. Ruptured hemangiosarcoma tumors on the spleen is a cause of collapse and sudden death in older dogs.
  • Liposarcoma In Dogs - Liposarcoma is a tumor that develops from fat tissue. Find them on the abdomen, limbs, or chest. They have a low to moderate chance of spreading, but they can get big enough to significantly damage surrounding tissues and organs.


Cancer is not as common in cats as it is in dogs, though unfortunately, it still exists.

  • Fibrous (Fibroid) Sarcoma In Cats - Fibrous (or fibroid) Sarcoma In cats is cancer that develops in the fibroblast cells (the most abundant cell in cat connective tissue). It has a low to moderate chance of spreading.


Lumps are quite common on older dogs, and not all lumps are cancerous. There are some symptoms which set sarcoma cancer in dogs apart from other bumps:

  • Hard or soft lump either at the surface of the skin or just underneath it
  • Enlarged Lymph Nodes
  • Leg Problems
  • Bloated Stomach
  • Sudden Weight Loss
  • Rapidly Deteriorating Health

A less severe explanation for a lump under your dog’s skin is a lipoma. Lipomas are benign tumors, meaning they don’t spread to other areas in the body. They can feel like a deviled egg under the skin, and don’t usually cause problems unless they grow very large. If your dog has a lump under its skin, you’ll want to have your vet take a sample. He or she can examine the sample under a microscope to find out if your dog’s lump is a benign lipoma or something more serious.


If you suspect your dog or cat has a sarcoma, get them to a vet for diagnosis quickly.

Veterinarians will usually try to diagnose soft tissue sarcoma in dogs by using fine-needle aspiration; a thin needle is inserted into the lump to obtain a sample for testing.

If fine-needle aspiration is not possible, then a surgical biopsy can be carried out to determine the presence of a sarcoma.

If the sample confirms that your dog or cat has a sarcoma, then further testing will likely be carried out to determine the best course of action, including radiographs, ultrasounds, and blood work.


  • Surgery – Surgery is the most common treatment for sarcomas in dogs. In some cases, one operation can cleanly remove the tumor, though a second surgery is sometimes required.
  • Radiation Therapy – Veterinarians will often use radiation therapy to stop or slow a tumor from coming back; it is also an option when surgery isn’t possible.
  • Chemotherapy – Chemotherapy slows or stops high-grade sarcomas from spreading.


There is no evidence to suggest that CBD will cure sarcoma in dogs and cats. However, we were able to find 13 studies that indicate CBD and other cannabinoids may slow or stop certain tumor growth in humans and animals.

At this time, there is not enough research to suggest that CBD should be a stand-alone treatment for soft tissue Sarcoma in dogs. Still, it might have the potential to work alongside traditional veterinary medicine and enhance its effects.

We found the following quotes in the summary of a February 2019 review of many scientific studies titled: Cannabinoids in Cancer Treatment: Therapeutic Potential and Legislation.

While it's apparent that CBD has the potential to aide various ailments, it is also clear that we are in the early stages of scientific research.

You should always consult your veterinarian if you suspect your pet has a soft tissue sarcoma, they will advise you on the appropriate treatment.


The life expectancy of dogs that have soft tissue sarcoma depends mostly on the grade of the tumor.

The good news is that, with treatment, there's only about a 20% chance that a low to intermediate-grade sarcoma will spread to surrounding organs.

The outlook isn’t so bright for high-grade sarcomas. Surgery, Radiation therapy, and chemotherapy can slow tumors down, but they will make it to organs in roughly 50% of dogs.


Biscuit's Story

I was unprepared for what would happen to my dog, Biscuit. 

Ever since she was a puppy, she’d spend her days running and playing. I’d take her on walks, to the beach, and dog parks.

Unfortunately, at age 10, she started to limp after trips to the beach. It broke my heart to see her in pain doing what she loved the most. I started feeding her a raw food diet and added high-quality supplements to ensure her nutritional needs were met. Unfortunately, while she loved the food, the limping persisted.

I went to the vet, who looked over Biscuit and said she was likely limping due to joint inflammation. She gave us something to help. This worked well at first. Biscuit was moving around more freely, and was limping less. 

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