What is it?

Hemangiosarcoma (HSA) is an aggressive, malignant cancer of blood vessels that often grows as a mass in the spleen, liver, or heart, but can also be found growing in other places in the body. Animals usually present to their veterinarian for sudden collapse due to internal bleeding from the mass. In most cases, by the time the animal is showing clinical signs, the cancer has spread to other areas of the body, such as the lungs. Diagnosis of HSA is suggested by chest and abdominal radiographs (x-rays), abdominal ultrasound and aspiration of abdominal fluid, and biopsy of the mass via exploratory surgery.

How is it treated?

Unfortunately, while there are treatment options available, there are no cures for this disease. While surgery may be an effective option for removing the primary tumor and temporarily stopping bleeding, it is not capable of removing all of the metastatic disease, which is usually microscopic at the time of diagnosis. Chemotherapy is often used in conjunction with surgery to help combat the microscopic cancer cells.

What is the prognosis for hemangiosarcoma (HSA)?

A diagnosis of HSA almost always carries a poor prognosis, the only exception being dermal HSA originating from the skin with no internal involvement. If treatment is not an option, euthanasia should be considered to prevent suffering from internal bleeding. Surgery alone to remove the primary tumor carries a median survival time of 1-4 months, while chemotherapy in addition to surgery carries a median survival time of 6-8 months.
Even with surgery and chemotherapy, the disease will progress and the cancer cells with continue to metastasize, creating masses throughout the entire body. Hemorrhages may occur from each cancer site, which may cause transient weakness until the bleeding stops. If the bleeding does not stop, the patient will start to show signs of shock and collapse. A personalized treatment plan is important to slow the progression of HSA. Talk to your veterinarian regarding the best treatment protocol for your pet.

What symptoms can present as the disease progresses?

Early stages:

  • loss of appetite
  • weight loss
  • lethargy
  • exercise intolerance
  • vomiting/diarrhea
  • pale gums
  • possible distended abdomen

Late stages:

  • persistent early stages
  • reclusive behavior
  • distended abdomen
  • dull mentation
  • difficulty breathing
  • panting, gasping for breath
  • possible black, tarry stool
  • sudden collapse
  • unable to rise

Crisis – Immediate veterinary assistance needed regardless of the disease

  • Difficulty breathing
  • Prolonged seizures
  • Uncontrollable vomiting/diarrhea
  • Sudden collapse
  • Profuse bleeding – internal or external
  • Crying/whining from pain*

*It should be noted that most animals will instinctually hide their pain. Vocalization of any sort that is out of the ordinary for your pet may indicate that their pain and anxiety has become too much for them to bear. If your pet vocalizes due to pain or anxiety, please consult with your tending veterinarian immediately.

Common Signs of Pain

  • Panting
  • Lameness
  • Difficulty sleeping
  • Pacing
  • Abnormal posture
  • Body tensing
  • Poor grooming habits
  • Tucked tail
  • Dilated Pupils
  • Licking sore spot
  • Muscle atrophy
  • Decreased appetite
  • Vocalizing/yowling
  • Reclusive Behavior
  • Aggressive Behavior
  • Avoiding stairs/jumping
  • Depressed
  • Unable to stand

Download Hemangiosarcoma brochure