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Hemangiosarcoma and Golden Retrievers

By JoAnna Pendergrass, DVM
published: September 6, 2019 - updated: February 22, 2023 • 3 min. read
healthy paws golden retriever

Key Takeaways

  • Hemangiosarcoma is an aggressive cancer in dogs.
  • These tumors are usually located in the spleen.
  • Anorexia, lethargy, and weakness are signs of hemangiosarcoma.
  • The primary treatment for this cancer is removal of the entire spleen.
  • Golden retrievers are especially prone to developing hemangiosarcoma.

A distraught pet parent rushes into the emergency veterinary clinic, carrying his Golden Retriever in his arms. His dog collapsed suddenly at home and is not doing well. What happened?

It is possible that this Golden Retriever has hemangiosarcoma, which is a very aggressive cancer in dogs. Hemangiosarcomas can seemingly strike without warning, leaving dogs very ill and causing pet parents and veterinarians to have to think quickly about what to do next.

What is hemangiosarcoma?

Hemangiosarcomas (HSAs) originate from endothelial cells that line the blood vessels. Although these tumors are primarily located in the spleen, they can also be found in the heart, kidneys, liver, muscle, and skin. In Golden Retrievers, HSAs are most common in the spleen and heart. What causes HSAs remains unknown.

Other than Golden Retrievers, German Shepherds and Labrador Retrievers are also susceptible to developing HSAs. This tumor typically affects middle-aged to older dogs, with the average age at diagnosis being 9 to 12 years.


Clinical signs

Clinical signs of HSAs are related to the tumor’s rupture and hemorrhage. Some of these signs, such as anorexia, lethargy, and weakness, are non-specific and therefore don’t immediately suggest cancer. Also, because the tumor may rupture only a little bit at a time, these general clinical signs may wax and wane. Unfortunately, it is common for dogs to experience sudden collapse due to a massive tumor rupture and hemorrhage. Major ruptures cause the blood pressure to plummet and will quickly send a dog into shock, which can be fatal.

Clinical signs also depend on the tumor’s location. For example, a massive rupture of a splenic HSA can cause a dog’s abdomen to fill with blood. A ruptured cardiac HSA can cause muffled heart sounds, irregular heart rhythms, and signs of heart failure like fluid in the abdomen and difficulty breathing.

During a physical examination of a dog with a ruptured HSA, a veterinarian will observe other signs such as pale mucous membranes, elevated heart and respiratory rates, and nosebleeds, all of which would be due to the tumor’s rupture.


In addition to a physical examination, a veterinarian will perform other diagnostic tests, described below, to confirm the presence of HSA.

  • An abdominal tap, which involves the removal and analysis of abdominal fluid, might reveal bright red blood (evidence of a splenic rupture) or other fluid (evidence of heart failure).
  • Abdominal ultrasound and abdominal x-rays could reveal abdominal fluid and masses on the spleen or other abdominal organs. However, a blood- or fluid-filled abdomen can make it challenging to find the spleen during imaging.
  • Blood work would indicate anemia, thrombocytopenia (decreased platelet count), and abnormal coagulation.
  • Echocardiography (heart ultrasound) could reveal a mass on the heart.

As mentioned above, HSAs are very aggressive and spread quickly throughout the body. In many cases, by the time a Golden Retriever has been diagnosed with HSA, the tumor has likely already spread.


Let’s go back to the pet parent at the emergency veterinary clinic. His dog has just been diagnosed with HSA on the heart and spleen, and the prognosis is very poor. He now faces a difficult decision: should he opt for treatment to remove the tumor or euthanize his beloved pet?

The main treatment for HSA is surgery. Surgical treatment for a splenic HSA is a splenectomy, which is the removal of the entire spleen. For a cardiac HSA, aggressive surgical treatment includes removing the tumor and part of the pericardial sac, a structure that surrounds and protects the heart.

Another treatment option is chemotherapy, which can be used in conjunction with surgery and can extend the survival time after surgery by up to several months. Immunotherapy, which uses the immune system to fight cancer, is currently being tested for its role in treating HSA.

Even with surgery and chemotherapy, a Golden Retriever with HSA has only a few months to live following diagnosis. The decision that a pet parent makes regarding whether to treat or euthanize their pet following a diagnosis of HSA is a personal one.

Closing Thoughts

Hemangiosarcoma is an aggressive cancer that can quickly make dogs very ill. Golden Retrievers are especially susceptible to this cancer. If you have a Golden Retriever, take him to your veterinarian immediately if you notice symptoms that might indicate HSA.

The content is not intended to be a substitute for professional veterinarian advice, diagnosis, or treatment. Always seek the advice of your veterinarian or other qualified health provider with any questions you may have regarding a medical diagnosis, condition, or treatment options.

Content provided by JoAnna Pendergrass, DVM. Dr. Pendergrass is owner and founder of JPen Communications, a medical communications company specializing in consumer education.

joanna pendergrass
By JoAnna Pendergrass, DVM

JoAnna Pendergrass, DVM, is a veterinarian and freelance medical writer in Atlanta, GA. After graduating from the Virginia-Maryland College of Veterinary Medicine with her veterinary degree, JoAnna completed a 2-year research fellowship in neuroscience at Emory University. During this fellowship, she learned that she could make a career out of combining her loves of science and writing. As a medical writer, JoAnna is passionate about providing pet parents at Healthy Paws with clear, concise, and engaging information about pet care. Through her writing, she strives not only to educate pet parents, but also empower them to make good health decisions for their pets. JoAnna is a member of the American Medical Writers Association and Dog Writers Association of America.

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