Hemangiosarcoma (HSA) is an aggressive cancer that can affect any dog regardless of breed, sex or age. It is a cancer that arises out of blood vessels and may appear as one or multiple tumours. This type of cancer can occur anywhere on the dog's body, but the most common affected organ is the spleen, accounting for 45 to 51 per cent of spleen canine cancers.
Collapse or sudden weakness
Collapse is a symptom of spleen cancer in dogs. Sudden weakness or collapse is usually related to spleen tumours rupturing, according to Alta Rancho Pet and Bird Hospital in Rancho Cucamonga, Calif. The tumour, single or multiple, eventually ruptures and bleeds internally. The internal loss of blood, which may be slow or fast, leads to the weakness. Blood loss also explains the collapse or sudden fainting of the dog.
Abdominal swelling and lack of appetite
Abdominal swelling is one of the symptoms of spleen cancer in dogs. The internal cancer is usually diagnosed by the palpation of a mass in the dog's abdomen causing it to be swollen, which may also cause loss of appetite. Additionally, the tumour's rupture can result in the loss of blood into the dog's abdomen, which could also inhibit the animal's desire to eat.
Chronic weakness is another sign of hemangiosarcomas, according to "Pet Cancer Center." The internal bleeding and discomfort of the tumour masses can reduce the pet's energy levels. This lethargy can also be the result of other symptoms of hemangiosarcomas, such as abdominal swelling and lack of appetite.