Hemangiosarcoma in Dogs: Types, Treatment, Diagnosis and Prognosis as Advised by Vets

Hemangiosarcoma is a form of canine cancer that develops in the endothelial cells – a layer of cells that line the inner walls of the blood vessels. 

In this article, we discuss the types of hemangiosarcoma in dogs, their signs, possible treatment options, and prognosis of this disease.

We’d like to extend our thanks to the following contributors for their insightful inputs towards this topic:

  • Dr. Sarah Wooten (DVM, CVJ) from Pumpkin Pet Insurance
  • Dr. Heather Venkat (DVM, MPH, DACVPM) from VIP Puppies
  • Dr. Michelle Burch (DVM) from Safe Hounds Pet Insurance

  • *Disclaimer: The information in this article is not meant to replace the advice and expertise of vets. You should consult a vet on your dog’s health condition for an accurate diagnosis.

    Summary of Hemangiosarcoma in Dogs

    Summary of Hemangiosarcoma in Dogs

    Dog Breeds Prone to Hemangiosarcoma

    Dogs of any breeds are susceptible to hemangiosarcoma. However, according to Dr. Venkat, this disease appears more commonly in breeds such as 

    Types of Hemangiosarcoma in Dogs

    Types of Hemangiosarcoma in Dogs

    Dermal Hemangiosarcoma

    Signs and symptoms
    • Red to purple growths on the skin
    • Bleeding due to the rupturing of the growth

    Dermal hemangiosarcoma develops on the skin of dogs.

    Dr. Burch shares that dermal hemangiosarcoma tumours are associated with sun exposure. In addition, they tend to form on areas of a dog with minimal or no fur such as his belly or on areas of white fur.

    Subcutaneous Hemangiosarcoma

    Signs and symptoms
    • Dark red to black growths under the skin

    Hemangiosarcoma can also form on the subcutaneous tissue (the layer of tissue just below the skin). 

    This type of cancer is known to be more aggressive than its dermal form; up to 60% of cases with this form of cancer experience the spreading of cancer cells.

    Visceral Hemangiosarcoma

    Signs and symptoms
    Clinical signs of visceral hemangiosarcoma vary depending on the location of the tumor.

    However, pet owners can still look out for symptoms of internal bleeding in their pet which includes:
    • Unexplained weight loss
    • Lethargy
    • Decreased appetite
    • Increased panting
    • Pale gums

    Visceral hemangiosarcoma primarily affects the spleen, liver, and heart of dogs. It’s an invasive and fast-spreading condition that’s life-threatening as tumours can break open, resulting in internal bleeding. 

    How to Diagnose Hemangiosarcoma in Dogs

    Dog lying down on a bed at the vet clinic

    Physical Examination

    If hemangiosarcoma is suspected, your veterinarian will request for a thorough history of your dog’s symptoms.

    He’ll then perform a physical exam on your pet. In some situations, the size of the tumours can grow large enough that they can be felt during the exam. 


    According to Dr. Wooten, hemangiosarcoma is also diagnosed through a biopsy – a procedure that involves removing tissue or sample cells from your dog’s body. 

    After the procedure, tissues or cells are analysed and the result of the analysis is used to determine the extent of your dog’s condition. 

    Diagnostic Tests

    Diagnostic tests will also be performed to confirm the diagnosis and rule out other causes of your dog’s symptoms.

    These tests may include:

      Complete blood count (CBC)
    This test is used to evaluate the overall health of your pet.

      Urine tests
    Urine tests are used to detect the presence of urinary tract infections and other diseases.

      Thyroid test
    A screening test used to uncover any issues with the thyroid gland.

     Electrocardiography (ECG)
    ECG is used to check the rhythm of your dog’s heart. An abnormal heart rhythm may indicate underlying heart diseases.

     X-rays and ultrasound of the chest and abdomen
    These are used to evaluate the spread of the cancer.

    Treatment for Hemangiosarcoma in Dogs

    Dog lying down

    Treatment for hemangiosarcoma depends on a host of factors such as 

    • the size of the tumour, 
    • its location, 
    • type of cancer,
    • and whether the cancer has spread. 

    Expanding on the points above, Dr. Venkat also shares that the treatment options vary depending on the type of hemangiosarcoma.

    Some pets may only require surgery while others may need radiation or chemotherapy due to metastasis (the spread of cancer).


    In most cases, the most effective form of treatment is the surgical removal of the tumour.


    Chemotherapy is often performed following surgery. Additionally, it’s also the main treatment for hemangiosarcoma in the heart as it’s difficult to carry out surgery in this part of the body.

    Radiation Therapy

    Your vet may also recommend radiation therapy if surgery cannot be used to remove the tumor. 

    Supportive Care

    You may also choose not to pursue treatment for your pet. In such cases, your vet will work closely with you to cope with your dog’s illness while helping him maintain a good quality of life.

    Prognosis of Hemangiosarcoma in Dogs

    Dog lying down on a table

    Unfortunately, the long-term prognosis for hemangiosarcoma is poor. It’s very aggressive and has a high mortality rate.

    The estimated survival time after surgery and chemotherapy is about 5 – 7 months. Furthermore, only about 10% of the dogs that have undergone treatment survive for up to 1 year.

    Managing Hemangiosarcoma in Dogs

    Early detection is imperative when dealing with hemangiosarcoma in dogs. You should consult your vet immediately if you sense that something’s amiss with your pet or if he’s displaying any of the symptoms listed above.

    Additionally, you should also consider purchasing pet insurance to help you manage the cost of treating your furry friend.


    • Madeleine Seah


      As an avid home baker, Madeleine spends a significant portion of her free time scouring the internet for recipes for next her baking project. When she’s not hands deep in kneading some form of dough, you can find her making music with a bunch of like-minded musicians at her alma mater’s alumni band.

    • Bernice Quek


      Intrigued by celebrity and influencer gossips, Bernice is passionate about finding the latest scandals and good deals to get a bang for her buck! Her closest friends know her as someone who has an irrational love for Disney's Stitch and an unwavering loyalty to KOI.


    Now hiring: retail assistants, warehouse assistants, pet groomers, pet care consultants & pet guardians.