Hemangiosarcoma in Cats
Dr. Kimberly Cronin
Hemangiosarcoma is a malignant cancer of the cells that form blood vessels. Because these tumors start in blood vessels, they are frequently filled with blood. Consequently, when a blood-filled tumor ruptures, it can cause problems with internal or external bleeding. Hemangiosarcoma is considered to be a very aggressive tumor and can spread rapidly to other organs. When the tumor is located in the spleen or liver, the signs are usually due to rupture of the tumor and subsequent bleeding into the abdomen. This causes anemia, weakness and if the bleeding is severe, collapse. The gums may appear to be pale or white. In relatively few animals the diagnosis is made before the tumor ruptures.
In cats, it occurs in older animals and there is no breed predisposition. Since this is a cancer of the blood vessels, it can start anywhere. In cats, this cancer occurs about half the time in internal organs (usually the spleen and liver) and half the time in the skin. These tumors usually spread to the lungs, liver, spleen and heart.
Signs of this disease are usually the result of the tumor rupturing, which causes bleeding. This may occur without any warning, and the symptoms will depend upon where the tumor is located.
When this type of tumor occurs in the heart, it can cause symptoms, such as weakness, collapse, difficulty breathing, exercise intolerance and fluid build-up in the abdomen. This is usually due to the development of fluid around the heart, called pericardial effusion. A thin sack, called the pericardium, normally surrounds the heart. In pericardial effusion the sack fills up with fluid and prevents the heart from beating effectively. With hemangiosarcoma, the pericardium fills up with blood due to rupture of the tumor.
When the tumor occurs in the skin, a mass or lump can usually be felt in or under the skin. The mass may become ulcerated and bleed. When the tumor occurs in a bone, it can cause pain and discomfort. In some locations, such as a rib, the tumor can be felt as a firm swelling in the bone.
What to Watch For
Anemia, weakness and collapse
Pale or white gums
Fluid build-up of the abdomen
Mass or lump under the skin
Swelling in the bone
Pain in the bones
Diagnostic tests that may be needed to recognize hemangiosarcoma and to direct treatment include:
Complete blood count (CBC) including platelet numbers
Serum chemistry panel and urinalysis
Abdominal radiographs (X-rays) and/or ultrasound
Ultrasound of the heart
The treatment and prognosis depends upon the location of the tumor. When the tumor occurs in an internal organ such as the spleen or heart, the chances of long-term survival are poor. Treatment is more successful when this cancer occurs in the skin.
Exposure to the sun may play a role in the development of this type of skin cancer. There is no known cause of hemangiosarcoma in other locations. In humans, exposure to certain chemicals (such as vinyl chloride) has been implicated as a cause.
Treatment for hemangiosarcoma may include the following:
Home Care and Prevention
Seek veterinary attention promptly if your pet develops pale gums, signs of weakness or collapse. Have any new lumps on your pet evaluated by your veterinarian.
Minimize your pet's exposure to the sun, especially cats that are poorly pigmented and have a sparse hair coat.