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Hemangiosarcoma in Cats: Causes, Symptoms & Care (Vet Answer)

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Last Updated on November 16, 2023 by Dr. Joanna Woodnutt, MRCVS (Vet)

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Written by

Dr. Joanna Woodnutt

MRCVS, Veterinarian

The information is current and up-to-date in accordance with the latest veterinarian research.

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Hemangiosarcoma is a fancy term for a type of cancer that invades and arises from the blood vessels in cats. It can occur in any part of the body, and it can also spread throughout the body, involving multiple organ systems. While it is a rare form of cancer in cats, it can often be quite aggressive when it occurs, and generally has a poor response to treatment, resulting in a high mortality rate.

There are two main types of hemangiosarcomas in cats: one that occur on the skin, and ones that occur internally. Skin hemangiosarcomas can be very unsightly, causing bleeding or redness of the skin, and be very irritating to cats and their owners. Internal hemangiosarcomas, and the associated clinical signs, will often be far more subtle—including weight loss, lethargy, and, overall, just not doing ok.

Treatment for both of these forms can include removal of the affected parts of organs, or skin, but often the hemangiosarcoma has already spread to other parts of the body by the time this has been pursued. There is presently no preventative known that helps with hemangiosarcomas.

Read on to learn more about hemangiosarcomas in cats—the causes, the care, and the treatment.

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What Causes Hemangiosarcomas in Cats?

Hemangiosarcomas are a type of cancerous growth that arises from blood vessels in cats. There is little data to show what causes these growths to occur in cats—unlike many other feline diseases, in which viruses, genetic traits, or other characteristics of the individual have been shown to play a role.

In other species, such as humans and mice, hemangiosarcomas are believed to have contributing factors, such as an individual’s genetics, or sun exposure.

Hemangiosarcomas can occur in different places on or in the body. If they occur on the skin, they are called “cutaneous hemangiosarcomas”. If they occur internally, in the liver or spleen, for instance, they are named after the organ in which they originate—such as, a “hepatic hemangiosarcoma”, or a “splenic hemangiosarcoma”.

Once they appear, they are often very quick to grow larger, and spread to other distant parts of the body.

Skin disease in a cat
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Where are the Symptoms of Hemangiosarcomas in Cats?

Symptoms of hemangiosarcomas can vary, depending on where in the body they occur. If on the skin, the symptoms can be relatively obvious. If internally, they can be far more subtle.

Symptoms can include:

  • Skin growths that can be red, raised, scabbed, or bloody
  • Hair loss
  • Lethargy or acting quite
  • Hiding or other changes in behavior
  • Weight loss
  • Inappetence
  • Pale gums or skin
  • A bloated abdomen
  • Abdominal pain or discomfort
  • Sudden collapse or fainting
  • Panting or open-mouth breathing

As with most diseases in cats, the more symptoms you see in your cat, the more concerned you should be. And remember, cats are masters at hiding signs of illness—so even a small concern that you note is worth reporting to your vet, in case your cat is hiding something bigger.

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How Can You Care for a Cat with Hemangiosarcoma?

The best care for a cat with a hemangiosarcoma is to have them seen by a veterinarian. This allows for a diagnosis to be confirmed, and for any treatment options to be discussed.

That said, sometimes, if a hemangiosarcoma is too invasive, or not amenable to treatment, palliative care may be the only option. Palliative care involves keeping a cat comfortable and happy on a day-to-day basis, while accepting that the underlying disease is allowed to run its course without treatment.

For some cats, palliative care may involve bandages of any skin growths, and care of those bandages (including bandage changes), or pain medications if the growths cause pain.

For other cats with internal hemangiosarcomas, if they are not actively bleeding, it may simply be lots of love, food, attention, and quiet time at home that makes the most comfortable. Your vet can help guide you on what care options exist, depending on your cat’s particular circumstances.

cat examined by Vets
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What are the Treatment Options for Cats with Hemangiosarcomas?

Treatment options can vary for cats with hemangiosarcomas. If it is confined to the skin, sometimes surgical removal will be advised. Note, however, that many times, even in spite of surgery, these growths will return, as they are difficult to fully remove. Chemotherapy is often not an option, though radiation therapy may be recommended in some instances.

If the hemangiosarcoma is internal, surgery may also be recommended. Sometimes, if the growth is actively bleeding, a blood transfusion (or two or three) may be needed prior to, or during, surgery.

As for cutaneous hemagiosarcomas, sometimes it can be difficult to remove the entire growth, and they may recur. In some instances, if the growths are invasive and large enough, your vet may make a recommendation that treatment is not pursued.

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Frequently Asked Questions (FAQs)

What should I do if I suspect my cat might have a hemangiosarcoma?

Speak with your vet if you suspect your cat might have a hemangiosarcoma! If it is a skin growth, start with a picture of the growth that you can share with your vet. This will also help you monitor how quickly it is growing, or changing.

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Are feline hemangiosarcomas contagious?

No evidence exists to show that feline hemangiosarcomas are contagious to other cats, pets, or people in the household.

What can look similar to hemangiosarcomas in cats?

Other skin cancers can often look very similar to cutaneous hemangiosarcomas. These can include: mast cell tumors, Bowenoid in situ carcinomas (BISC), and squamous cell carcinomas. Early hemangiosarcomas can look similar to actinic keratitis, a form of sunburn in cats, or even like bad flea or skin allergies.

Internal hemangiosarcomas obviously can’t be seen with the naked eye, but other bleeding cancers, such as adrenal tumors, liver tumors, or splenic tumors, can all cause similar presentation to internal hemangiosarcomas.

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Hemangiosarcomas in cats are less commonly seen than many other diseases, and certainly occur less frequently than they do in dogs. It is far easier to recognize the skin or cutaneous form when it occurs, but any signs of a cat not seeming quite right warrant a conversation, and generally, a trip to your veterinarian as well. Treatment is often unrewarding, although it can provide temporary cessation of clinical signs, such as bleeding. Many hemangiosarcomas that are removed will recur, however, and unfortunately, mortality due to the disease is high.

Featured Image Credit: eremeevdv, Shutterstock

About the Author

Dr. Joanna Woodnutt, MRCVS (Vet)
Dr. Joanna Woodnutt, MRCVS (Vet)
Joanna is an experienced veterinarian working in the UK. She has written about pets and pet health for many websites, blogs, and pet magazines and loves to help owners understand their pets through her writing.

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