Sarcomas are cancerous tumors that arise from the cells of blood vessels, nerves, muscles, connective tissues or fat. They are usually malignant, which means that they tend to worsen with time. Sarcomas can cause serous illness and, eventually, death. They typically grow slowly and spread (metastasize) only after they have been growing in one place for quite some time. Sarcomas can be well-defined and encapsulated, or they can have indistinct borders that infiltrate nearby areas, much like the tentacles of an octopus probing into surrounding tissues. Together, all the different types of sarcomas account for about 15% of recognized cancers in companion dogs.
Hemangiosarcoma is a particular type of sarcoma that arises from cells lining blood vessels – especially the smaller arteries and veins. The lining of blood vessels is called “vascular endothelium.” Arteries are the vessels that carry oxygenated blood from the heart and lungs to the rest of the body. Veins are the vessels that carry unoxygenated blood and waste products from body tissues back to the heart and lungs. Since hemangiosarcomas involve abnormal overgrowth of blood vessel tissues, they tend to bleed profusely when they are cut or disturbed. They are particularly fragile tumors that are prone to rupturing and causing internal bleeding that can be extremely dangerous - and often fatal - to the affected animal.
Other names for hemangiosarcoma are HAS, angiosarcoma and hemangioendothelioma. Hemangiosarcomas are common in dogs and rare in cats. Unlike some of the other canine sarcomas, hemangiosarcomas are very invasive, fast-growing tumors that often migrate to the spleen, heart, liver, lungs, kidneys, muscle, lymph nodes or skin. Usually, by the time hemangiosarcoma is diagnosed, it has already spread from its initial site to other places in the dog’s body.
The actual causes of hemangiosarcoma, like the causes of most other types of cancer, are not well understood. Hemangiosarcomas can develop anywhere on the surface of a dog’s body, inside its internal organs or within body cavities. Primary hemangiosarcomas tend to occur most frequently in the skin, heart, spleen, liver and bone. Wherever they start, hemangiosarcomas initially are formed from cells lining small blood vessels. They are predisposed to spreading rapidly to remote areas of
While it is difficult to say with certainty how a dog with hemangiosarcoma is affected by its condition, reports from people with this disease, and observations of dogs, suggest that hemangiosarcoma usually causes a great deal of discomfort and pain, especially in the later stages. The exact symptoms will depend upon the site of the primary tumor (liver, spleen, heart, skin, bone, other), and where the cancer has spread.Owners of dogs with hemangiosarcoma may notice
Hemangiosarcoma is usually diagnosed using X-rays (radiographs), ultrasonography (ultrasound), computed tomography (CT scan) and tissue biopsies of suspicious masses. Chest X-rays are especially useful to determine whether the cancer has spread to the lungs. Abdominal X-rays and abdominal ultrasound can also reveal spread of the cancer, especially if they show an enlarged liver or spleen. Of course, a complete history and a thorough physical examination are critical parts of the diagnostic process. The abdomen will
The main goals of treating hemangiosarcoma are to remove the tumors surgically if possible, minimize the chances of bleeding from tumor rupture and prolong the dog’s survival time and quality of life. If the cancer has spread to the spleen, that organ can be removed by a splenectomy. Unfortunately, depending upon the extent of local invasion of the cancer into surrounding areas, it is not always possible to remove all of the cancerous tissue. Radiation,