Hemangiosarcoma: What All Dog Owners Need to Know

Pets are one of the most important parts of our lives, but what happens when they get sick? We frantically worry about what they may pick up in their short time with us, and when they do get ill, we depend on the vet to fill us in on what went wrong. Sometimes, we catch the infection in time. Sometimes, it’s too late.

While there are millions of diseases our furry babies can catch, there is one in particular that can be deadly if it isn’t noticed or caught in time. Just like humans, dogs can also contract cancer. Cancer can come in many different forms, but one type in particular, known as hemangiosarcoma, is a type of cancer that rapidly grows and becomes highly invasive within dogs. While it doesn’t exclusively occur in dogs, it’s very rare that a cat will get it.

What is a hemangiosarcoma?

By definition, a hemangiosarcoma is an aggressive, malignant tumor of blood vessels. Because they start in blood vessels, it has a possibility to rupture, causing the likelihood for internal or external bleeding. Theoretically, they can rise from any tissue where there are blood vessels, but there are commonly three different types of hemangiosarcomas: dermal, hypedermal, and visceral (spleen and heart).

• Dermal hemangiosarcomas, which tend to appear on visible skin, are the easiest to take care of surgically and have the greatest potential for complete.
• Hypedermal or subcutaneous hemangiosarcomas are usually normal to spot, but have a large chance of spreading internally.
• Visceral hemangiosarcomas, which can occur on both the spleen and the heart are the most serious. The spleen is an important organ for blood and lymph functions, but hemangiosarcomas that grow on them tend to break open and bleed profusely. While there is a way to remove the danger of this rupture, it does not guarantee that the hemangiosarcoma is gone for good. If a hemangiosarcoma grows on the heart, it tends to be a life-threatening situation. If the sarcoma ruptures on the heart, it can fill up the sac, also known as the pericardium, putting pressure on the heart itself, causing it to have no room to pump the necessary blood.

How do you know if your pup has a hemangiosarcoma?

Since most hemangiosarcomas occur in internal organs, it is hard to diagnose your dog until they start showing severe symptoms. The most obvious signs are usually a result of the tumor rupturing, causing it to bleed. It will occur without warning, and symptoms will be different depending on where the tumor is located. If your pet has a dermal hemangiosarcoma, it is usually visible or easy to feel for. The mass or lump will either be in or just under the skin and can become ulcerated and bleed. Common symptoms of hypedermal hemangiosarcoma, include nose bleeds, obvious bleeding, tiring easily, episodes of weakness, pale gums, difficulty breathing, abdominal swelling, seizures, abnormal heart rhythms, and depression. If the hemangiosarcoma is located on the spleen, symptoms can include pale gums, anemia and collapsing. However, it is possible to catch this type of sarcoma before it ruptures.  If the hemangiosarcoma is located on the heart, the symptoms can include weakness, difficulty breathing, collapse, intolerance to exercise, and fluid build-up in the abdomen.

How are hemangiosarcomas treated?

In order to treat hemangiosarcomas, it depends on where it’s located on your dog. While dermal sarcomas are easier to treat and have a greater survival rate, visceral sarcomas are much more aggressive and harder to treat. Most of the time, treatment of the visceral sarcomas have little to no impact. If the tumor is identified when it is small, it may be possible to remove the spleen or the pericardial sac, but by the time the tumor is found, it is likely that the malignant tumors have already begun to spread throughout the dog. The cause of the tumor is linked to sun exposure and certain chemicals, like vinyl chloride. It may also be due to a genetic link. However, the true cause of this aggressive cancer is still very limited, making it hard to prevent.

If you’re still curious about hemangiosarcomas, call or visit your veterinarian to discuss what to do if you believe your pet has it or may contract it. This cancer is very intrusive and deadly, and should not be taken lightly.