Signs & Symptoms of a Bleeding Tumor in the Abdomen of a Dog

Updated July 20, 2017

When a hemangiosarcoma, a canine tumour, strikes it hijacks the dog's blood vessels and creates a blood-filled tumour which can cause severe bodily damage or death if it ruptures. This aggressive cancer strikes quickly and can spread to other organs. Awareness of the warning signs of a bleeding tumour could save your dog's life in a crisis situation.

Look For a Swollen Hard Mass

Generally, hemangiosarcoma has no signs until the tumour ruptures. However, in some cases the dog develops a hard lump in its abdomen. Perform an occasional tactile check on the dog by rubbing along its abdomen; look for the sudden appearance of a hard lump. Dogs have a higher chance of surviving hemangiosarcoma if detected early and treated by a veterinarian, especially if it has yet to spread to other internal organs.

Sudden Swelling of the Abdomen

Hemangiosarcoma tumours usually appear on vital organs, most often the spleen, liver or heart. When the tumour bursts the dog's body swells as its blood fills its abdomen. This sudden internal bleeding threatens the dogs life; without medical intervention most dogs only survive a few hours after a tumour bursts. Immediately take any animal with balloon-like swelling to an emergency veterinarian even if it has no other signs of hemangiosarcoma.

Changes in Behavior

When dogs develop a cancerous tumour their mood and behaviour often changes. Listless behaviour and sudden fatigue indicate blood loss from a bleeding abdominal tumour. Additionally, a burst tumour causes anaemia which results in a loss of colour; check that the dog's gums are pink because white gums indicate a problem. The dog may also show impaired breathing or heart irregularities. Finally, a canine seizure can indicate a burst tumour in an animal who has never seized before.


Dogs do not routinely collapse; any collapse is serious and life threatening. When a dog collapses from a burst tumour it means the blood filling its abdomen is diverting oxygen away from its brain. Even when the dog has shown no other signs of hemangiosarcoma, collapse indicates a major problem, like heat stroke or heart attack. Seek veterinary assistance immediately following a dog's collapse.

Cite this Article A tool to create a citation to reference this article Cite this Article

About the Author

Sarah Wallman has been writing in newspapers since 2004 in publications such as the "Spectator." Her primary interests are health, religion, politics and psychology. She has earned two bachelor's degrees, and has a passion for providing information on health and fitness.