Hemangiosarcoma in Dogs

Written on May 03, 2019 by Staff Veterinarian

Golden Outside on Pathway with Grass

Cancer is unfortunately common in older dogs. Hemangiosarcoma is one of the more serious and rapidly growing forms of cancer found in dogs. Here’s what you need to know:

What is Hemangiosarcoma?

Hemangiosarcoma is a malignant tumor that lines the blood vessels. Large breed dogs are more commonly affected, especially middle aged to older breeds including:

  • German Shepherds
  • Labrador Retrievers
  • Golden Retrievers

Though ANY dog can develop Hemangiosarcoma.

There are 3 forms of Hemangiosarcoma:

  • Dermal (skin)
  • Subcutaneous (the layer beneath the skin)
  • Visceral (spleen, heart, liver, kidneys, and/or bladder)

Clinical signs

Many times, dogs with Hemangiosarcoma may show non-specific signs if small hemorrhages of the tumor occur repeatedly, such as:

  • lethargy
  • anorexia (not eating)

Unfortunately, other common and more severe symptoms may include:

  • collapse
  • increased heart rate/respiratory rate
  • pale mucous membranes caused by substantial hemorrhage of a ruptured tumor


Many dogs with the splenic form present for rupture of the tumor and bleeding within the abdomen. The following diagnostics may be recommended:

  • abdominal tap
  • abdominal ultrasound
  • radiographs
  • aspirates and biopsies of splenic masses
  • blood work
  • surgical removal of the spleen

Additionally, any associated masses may need to be sent for histology for diagnosis and an echocardiogram may be recommended to evaluate for heart masses.

Approximately 10-20% of dogs with splenic Hemangiosarcoma will have right atrial involvement.


Often times, because dogs present due to substantial hemorrhage, owners will have to make a difficult decision between an emergency surgery to remove the bleeding tumor, or humane euthanasia.

The prognosis for patients that have Hemangiosarcoma of the spleen following surgery alone is approximately 2 months with only 10% survival at one year. The average survival time with surgery and chemotherapy is improved at 6-8 months and patients typically experience an excellent quality of life during treatment.


Much of the prevention is focused on the dermal form. If your pet has light skin, short hair or has a thin haircoat it’s best to limit direct exposure to the sun or applying a pet safe sunscreen. At this time there is no prevention for visceral (spleen, heart, liver etc).

And there is no cure.

Support the Cause

Ethos Discovery, our 501(c)3 nonprofit is currently conducting studies and research to find a cure for canine Hemangiosarcoma. Click here to learn more.


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