Hemangiosarcoma in Dogs

Hemangiosarcoma is a form of malignant cancer that arises from the cells that line blood vessels of various tissues of the body. The most common location of this tumor is the spleen, but tumors can grow anywhere blood vessels are present and can spread to other organs, including the lungs and heart. Hemangiosarcoma is considered to be a very aggressive form of cancer and is most common in medium- sized or larger and middle-aged or older dogs. German shepherds are widely considered to be a breed that is at high risk for developing this type of cancer.

Because hemangiosarcoma tumors grow internally, there is often very little warning until severe symptoms occur. The tumors invade and erode blood vessels, which can cause a considerable amount of blood to seep into the abdominal or, less commonly, the thoracic (chest) cavity.

When a dog finally begins to show symptoms, they usually present as the following:

  • Lethargy; tiring easily 
  • Weakness
  • Pale mucous membranes (mouth and eyes)
  • Rapid or labored breathing
  • Abdominal swelling; “pot-bellied” appearance 
  • Depression
  • Lack of appetite
  • Nosebleeds

Your veterinarian will take a complete history of your dog’s activities and symptoms, and will also perform a thorough physical exam of your pet. In some cases, these tumors are so large they can be felt during the physical exam. In all situations, your veterinarian will recommend diagnostic tests to confirm the diagnosis, rule out other causes of your dog’s symptoms, and assess your dog’s overall health.

These may include:

  • Chemistry tests to evaluate kidney, liver, and pancreatic function, as well as sugar levels
  • Clotting tests to evaluate the ability of your pet’s blood to clot properly
  • Blood parasite screening to identify if your pet has been exposed to tick-borne or other infectious diseases
  • Fecal tests to rule out intestinal parasites 
  • A complete blood count (CBC) to rule out blood-related conditions
  • Electrolyte tests to ensure your pet isn’t dehydrated or suffering from an electrolyte imbalance
  • Urine tests to screen for urinary tract infections and other diseases, and to evaluate the kidney’s ability to concentrate urine
  • A thyroid test to determine if the thyroid gland is producing too little thyroid hormone
  • An ECG to screen for an abnormal heart rhythm, which may indicate underlying heart disease
  • X-rays of the chest and abdomen
  • Ultrasound of the chest and abdomen

Treatment for hemangiosarcoma will depend on a variety of factors including the size of the tumor, its location, and whether the cancer has spread (metastasized). Treatment may include surgical removal of the tumor, chemotherapy, and/or supportive care. The prognosis for dogs with hemangiosarcoma is guarded because of the aggressive nature of this type of cancer.

Unfortunately, there is nothing that can be done to prevent hemangiosarcoma. Early detection and supportive care, however, can enhance your four-legged friend’s quality of life.

If you have any questions or concerns, you should always visit or call your veterinarian – they are your best resource to ensure the health and well-being of your pets.