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Bleeding Tumors in a Dog's Abdomen

Sensitive Periods in Dogs

Bleeding tumors in a dog's abdomen are concerning because they can have critical repercussions on the dog leading to potentially life-threatening situations. If your dog was diagnosed with bleeding tumors, consider learning more about how these can impact your dog and how to recognize early signs of trouble requiring a prompt veterinary visit. Close monitoring is important. Veterinarian Dr. Ivana Crnec provides information about bleeding tumors in a dog's abdomen, the most common types and treatment options.

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Bleeding Tumors in a Dog's Abdomen

The first thing that comes to mind when talking about internal bleeding is trauma. Being hit by a car or falling from significant height are common causes of internal bleeding. Another common cause of internal bleeding in dogs is ingestion of rat poison. But what about dogs with no history of traffic accidents, fallings, traumas and rat poison intoxication?

Well…although the above listed events are common culprits, the most common cause of internal bleeding in dogs is cancer. According to statistics, around 85 percent of all dogs presenting with an internal bleeding in the abdomen have cancer as an underlying culprit.

Hemangiomas and hemangiosarcomas are the most frequently diagnosed types of bleeding tumors in dogs. That is because these specific tumors are made of bunch of blood vessels. Hemangiomas are benign tumors, while hemangiosarcomas are malignant. Both types of tumors can form on any internal organ but they are usually found on the heart, liver and spleen. Sometimes, these tumors can form on the inside of the abdominal wall.

Although most hemangiomas and hemangiosarcomas are significantly large, they do not cause an issue until they rupture and consequently start bleeding. Logically, the bleeding is followed by anemia, labored breathing and general weakness.

Hemangiomas and hemangiosarcomas can occur in dogs of any breed and age. However, certain dog breeds, such as Labrador Retrievers, Golden Retrievers and German Shepherds are at higher risk of developing such tumors. Also, the risk is significantly higher in middle-aged and older dogs.

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Signs of Bleeding Tumors in a Dog's Abdomen

Since hemangiomas and hemangiosarcomas are particularly prone to affecting the dog's spleen and liver which are well-vascularized (rich in blood-vessels) organs, when such vascular organs start bleeding, the blood loss can be potentially life-threatening.

Hemangiomas and hemangiosarcomas are likely to bleed because their blood vessels do not have normal connections. Namely, normal blood vessels are well-connected. However, a tumor’s blood vessels lack strong connections, and are therefore, more likely to tear and consequently bleed.

Once the bleeding starts, the blood accumulates in the abdomen. The condition that manifests with accumulation of blood in the abdomen is medically termed as hemoabdomen.

Sadly, these tumors are an insidious condition that does not manifest until it is too late to do something. The related clinical signs and symptoms develop suddenly and progress quickly. Dogs with hemangioma or hemangiosarcoma will show the following signs and symptoms:

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  • Distended abdomen (hemoabdomen)
  • Frequent vomiting
  • Decreased appetite
  • General malaise
  • Labored breathing
  • Pale gums
  • Collapse

It should be noted that certain dogs can be asymptomatic. In those patient, the mass is found accidentally during regular ultrasound examinations.

At the Vet's Office

There are several steps used by veterinarians for diagnosing bleeding tumors in a dog’s abdomen:

  • Physical examination – in most cases, if the mass is large enough, an experienced vet will be able to palpate it in the abdomen
  • Radiographs of the belly – an x-ray image of the abdomen is necessary to determine the exact location of the mass
  • Radiographs of the chest – an x-ray image of the chest is necessary to search for evidence of cancer spread (metastasis to the lungs)
  • Ultrasound of the belly – an abdominal ultrasound in dogs is helpful to confirm the presence of fluid in the abdomen (this only confirms the presence of fluid, but it does not determine the type of fluid)
  • Abdominocentesis – includes taking out a sample of the accumulated fluid
  • Basic blood work – complete blood count as well as biochemistry parameters to determine whether the patient is suitable surgery candidate.

Generally speaking, there are three options for patients diagnosed with hemangioma or hemangiosarcoma on the spleen or liver. Those options include:

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Aggressive Approach 

This includes surgery to remove the bleeding tumor. If the tumor is on the spleen, the spleen is also removed. Therefore, in cases of hemangioma, removing the spleen is a curative procedure. If the tumor is on the liver, the liver cannot be completely removed. However, the affected portion of the liver should be taken out. Sadly the surgical approach is not always applicable. Surgery is the treatment of choice in patients with only one, easily removable tumor. In cases of multiple tumors, their removal is not achievable.

Additionally, in cases of hemangiosarcoma, the removal of the tumor and adjacent organ or tissue does not ensure positive outcome. This is because the hemangiosarcoma is an aggressive type of tumor that usually has metastasis on the lungs. If the malignancy of the tumor is determined, but there is minimal metastatic spread, once the primary tumor is removed, the patient may be put on chemotherapy which on the long-run increases the quality of life.

Palliative care

This includes using medication that will hopefully slow down the tumor’s growth and eventually delay the bleeding onset. Patients put on palliative care also need intravenous fluids as a supportive aid. This approach is recommended only for patients with non-bleeding, benign tumors.

If the tumor is bleeding, the palliative care is not enough. It is worth mentioning that on rare occasions, these tumors can stop bleeding on their own. However, unless removed, it is only a matter of time until they start bleeding again.


This option is the last resort and it should only be considered if there is no other way. Euthanasia is recommended for patients with advanced types of hemagiosarcomas (with lung metastasis) and for patients that are either too weak or too old to be subjected to surgery.


The prognosis depends on the type of tumor, its location and the treatment of choice. Generally speaking, dogs that responded well to the removal surgery have an average survival time of 2 to 3 months. Then, the cancer comes back and more often not, this time, it cannot be surgically removed. The survival rate of dogs on palliative care varies from few days to few weeks after diagnosis.

About the Author

Dr. Ivana Crnec is a graduate of the University Sv. Kliment Ohridski’s Faculty of Veterinary Medicine in Bitola, Republic of Macedonia.

ivana crnec

She currently practices as a veterinarian in Bitola and is completing her postgraduate studies in the Pathology of Domestic Carnivores at the Faculty of Veterinary Medicine in Zagreb, Croatia.

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