Hemangioma and Sarcoma in Dogs

By Jane Meggitt

Hemangiomas in dogs are generally benign soft tissues and skin tumors, while sarcomas are malignant tumors developing in the soft tissues. Hemangiosarcoma, or cancer of the blood vessels, is a type of tumor occurring more often in canines than any other animal. Unfortunately, hemangiosarcoma symptoms often don't become obvious until the cancer has already spread significantly. The prognosis for this disease isn't good, but treatment before the cancer spreads can lengthen an affected dog's life span.

Hemangiomas in Dogs

Hemangiomas are sort of the benign versions of malignant hemangiosarcomas. Both are considered vascular tumors. Hemangiomas resemble blood vessels on the skin. While benign, hemangiomas can bruise and ulcerate, so surgical removal is usually recommended. Once excised, they don't tend to grow back. Certain breeds, including boxers, Scotch terriers and Airedales are prone to developing hemangiomas.

Soft Tissue Sarcomas in Dogs

Soft tissue sarcomas in canines can be benign or malignant. They aren't just one type of connective tissue tumor; they can include various growths, including fibrosarcomas, neurofibrosarcomas, liposarcoma, rhabdomyosarcomas and others. One type of this tumor can intertwine with another type. The deeper the sarcoma is within the animal's body, the more likely it's malignant. Treatment includes surgery, along with radiation and chemotherapy. If a dog's tumor can't be completely removed, or there's evidence of metastasis, or spreading, your vet might choose palliative radiation. This treatment relieves some of the pain associated with the growth but does not treat the cancer per se.

Hemangiosarcoma in Dogs

Although hemangiosarcoma starts in the blood vessels, tumors generally develop in the major organs, especially the liver and spleen. They also occur in the heart, bone, brain and kidneys. They tend to metastasize from these organs into the stomach or lungs. Hemangiosarcoma doesn't cause pain in the affected canine until it has spread quite widely.

Hemangiosarcoma symptoms include breathing difficulties, lethargy, abdominal swelling, pale gums, exercise intolerance, rapid heartbeat, appetite and weight loss, lameness, partial paralysis, seizures and sudden collapse. Hemorrhaging is possible. Unfortunately, sometimes the first and only sign of hemangiosarcoma is the dog's sudden death.

Your vet will conduct blood tests and a urinalysis, along with X-rays and ultrasounds to detect masses in the organs. She might also perform an endoscopy to biopsy a tumor, leading to a conclusive diagnosis. Standard treatment includes surgical removal of the tumor, followed by chemotherapy. However, some dogs aren't candidates for surgery because of the tumor location. If a dog undergoes surgery but doesn't receive chemotherapy, the average survival time is three months. If he does receives chemotherapy, the average survival time is twice as long -- six months.

Dermal and Subcutaneous Hemangiosarcoma

If your dog is diagnosed with skin hemangiosarcoma, rather than the type affecting the internal organs, a cure is possible if the disease is caught early. Hemangiosarcoma in a dog's skin is either dermal or subcutaneous. Short-haired, light-colored dogs are most likely to develop these forms of hemangiosarcoma. The growth is dark or red. If your pet has any lumps or bumps on his skin, take him to the vet as soon as possible for an examination. If the dermal type is removed promptly, the dog may completely recover. Besides surgery, a dog with dermal hemangiosarcoma may also receive radiation therapy. The majority of subcutaneous growths have already metastasized, so the prognosis is not so good for this type of skin hemangiosarcoma.

Affected Breeds

While any dog can develop hemangiosarcoma, certain breeds appear to have a genetic predisposition toward the disease. These include the golden retriever, the boxer, the German shepherd, the Doberman pinscher, the Labrador retriever, the Great Dane, the English setter, the Portuguese water dog, the Bernese mountain dog, the flat-coated retriever and the Skye terrier. Hemangiosarcoma appears more often in male dogs than in females. Dogs usually develop symptoms after the age of 6; median age of diagnosis is 10.