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Knowing when to euthanize a dog with hemangiosarcoma is something dog owners may wonder about. 

Hemangiosarcoma in dogs is a common type of tumor, accounting for around 5 percent of all canine cancer cases. 

Hemangiosarcoma is a malignant tumor and results in a poor prognosis even in cases when prompt and adequate treatment is provided.

In this article, we will discuss what happens when dogs develop hemangiosarcoma and how it causes internal bleeding. We will talk about how cancer impacts dogs leading to weakness and anemia.

Then we will go into detail on the final stages of this cancer and when a dog with this condition should be euthanized. 

The dog’s quality of life should always be kept in mind. However, the euthanasia decision remains a personal choice.

What is Hemangiosarcoma in Dogs?

Hemangiosarcoma is a cancer type that stems from cells lining the blood vessels. Even the name of the cancer is derived from this–hem, which means blood, angio which means a vessel, and sarcoma which means tumor.

Since blood vessels can be found everywhere around the body, hemangiosarcoma can develop in all places. However, the most common hemangiosarcoma locations are the skin, spleen, liver, and heart.

Like a malignant tumor, hemangiosarcoma is extremely aggressive–it invades the local tissues and has a spreading tendency (causing metastasis). Plus, the tumors are filled with blood and very fragile.

If a hemangiosarcoma ruptures (which is more common than one might think), it can result in massive and potentially life-threatening internal bleeding.

What are Different Types of Hemangiosarcomas in Dogs? 

As mentioned, there are different types of hemangiosarcoma based on location and affected organs. For easy understanding, vets classify hemangiosarcoma into two main types–visceral and cutaneous.

Let’s take a closer look at each hemangiosarcoma type.

Cutaneous Hemangiosarcoma

This hemangiosarcoma type develops in the lining of the blood vessels that nourish the surface dog’s skin. Cutaneous hemangiosarcoma in dogs is explicitly aggressive–both locally and in the form of causing distant metastasis.

Visceral Hemangiosarcoma

 As the name suggests, canine visceral hemangiosarcoma develops in the dog’s internal organs, most commonly the spleen. 

Same as the previous form, visceral hemangiosarcoma is invasive (destroys local tissues and produces metastasis).

Visceral or, better said, splenic hemangiosarcoma is the most common tumor type in dogs. The spleen is an important organ responsible for removing dead red blood cells from circulation and fighting infections.

Hemangiosarcoma of the spleen is known as splenic hemangiosarcoma, splenic HSA, and spleen cancer.

Causes and Risk Factors 

Sadly, the causes of hemangiosarcoma, same as the causes of many cancer types, are unknown. It is supposed that cancer develops as a result of several factors working at the same time.

Here are some of the factors linked with increased hemangiosarcoma risk in dogs:


Certain dog breeds are more likely to develop hemangiosarcoma than others. This fact supports the claim that cancer is genetic. 

Based on statistics, hemangiosarcoma is more common in medium and large-sized dog breeds. Some of the breeds prone to hemangiosarcoma are:

  • Labrador and Golden Retrievers
  • German Shepherds
  • Poodles
  • Whippets
  • Doberman Pinschers
  • Portuguese Water Dogs
  • Boxers
  • Basset Hounds
  • Great Danes
  • English Setters


 Almost all cancer types are more common in older dogs. When it comes to hemangiosarcoma, middle-aged and senior dogs are most affected.

Anyway, this does not mean that hemangiosarcoma cannot develop in young puppies and adult dogs.

Excess Sun Exposure

 Skin hemangiosarcoma is probably linked with sun exposure. Dogs with short hair and light skin are more frequently affected by cutaneous hemangiosarcoma, thus proving this claim. 

Plus, hemangiosarcoma of the skin usually develops on body parts lacking hair (nose and belly).

What are theSymptoms of Hemangiosarcoma in Dogs?

It is very hard for pet owners to spot the signs and symptoms of hemangiosarcoma in dogs. This is because of two main reasons.

First, the signs and symptoms depend on the hemangiosarcoma itself–the location and stage. Second, most of the signs and symptoms are non-specific–and can be the result of many health issues.

Cutaneous Hemangiosarcoma in Dogs

Skin hemangiosarcoma is easier to distinguish than visceral forms. Namely, a dog with cutaneous hemangiosarcoma is likely to have black or red growths on the skin.

 As time goes on, the masses can change color and even become ulcerated. In case of ulceration, they will start to bleed.

Visceral Hemangiosarcoma in Dogs

Visceral hemangiosarcoma in dogs is more challenging because it develops in different spots. For a simpler understanding, we will go through the clinical signs and symptoms of the most common types of visceral hemangiosarcoma in dogs.

A dog with heart hemangiosarcoma will show abnormal heart function and signs such as:

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  • Arrhythmia (irregular heartbeat)
  • Pericardial effusion (fluid build-up in the pericardial sac)
  • Exercise intolerance.

A dog with splenic hemangiosarcoma may not cause specific signs and symptoms until the mass ruptures, causing internal bleeding and issues like:

  • Pale gums
  • Abdominal distension
  • Tachycardia (increased heart rate)
  • Tachypnea (increased breathing rate)
  • Lethargy and weakness

Dogs with visceral hemangiosarcoma can also exhibit an array of non-specific signs and symptoms such as decreased activity levels, slow wound healing, nosebleeds, breathing problems, appetite changes, pale gums, etc.

The vet will also order some universal tests like blood analysis (complete blood count and biochemistry profile) to determine the dog’s overall health.

The vet will also order some universal tests like blood analysis (complete blood count and biochemistry profile) to determine the dog’s overall health.

Diagnosis of Hemangiosarcoma in Dogs

Diagnosing hemangiosarcoma starts with a regular physical examination. Even if the vet suspects the diagnosis, the protocol is to start with a full body examination.

 At the same time, the veterinarian will take the dog's history and discuss with the owner things that will help make the diagnostic process easier.

After the physical examination is done, the vet will recommend more specific tests. In general, dermal hemangiosarcoma is diagnosed via fine-needle aspiration (FNI). 

Do not be confused by the fancy name–FNI is a simple procedure in which the vet uses a small-gauge needle attached to a syringe to collect a cell sample from the growth. The collected sample is then analyzed under a microscope.

Visceral hemangiosarcoma requires more specific and various diagnostic tests and procedures such as radiography, ultrasonography, and advanced imaging techniques like CT scans and MRIs.

The vet will also order some universal tests like blood analysis (complete blood count and biochemistry profile) to determine the dog’s overall health.

When diagnosing hemangiosarcoma, vets need to rule out several conditions that manifest with similar clinical signs and symptoms. The potential differential diagnoses for hemangiosarcoma are:

  • Rodenticide poisoning
  • Splenic torsion
  • Hemangioma (benign version)
  • Hemolytic anemia.

Hemangiosarcoma Treatment 

There are different treatment options for dogs with hemangiosarcoma. The best treatment depends on several tumor factors and the dog’s overall health.

Let’s take a closer look at the different hemangiosarcoma treatments:


Surgical treatment is recommended for dogs with hemangiosarcoma that has not spread to distant organs. 

Usually, vets recommend surgery for cutaneous and subcutaneous hemangiosarcoma. Removing the tumor is not always a definitive cure. However, it improves the prognosis.


Chemo is a good treatment option in cases of metastasized hemangiosarcoma. When dealing with splenic hemangiosarcoma, vets use a chemotherapy drug called doxorubicin. Chemotherapy results in an average survival time of around six months.

Radiation Therapy

 Radiation is also suggested for dogs with metastasized hemangiosarcoma. Radiation therapy is not a cure, but when used together with other treatments, it can increase the dog's survival time.

In Cases of Instability 

Sometimes, the dog is not stable to start a treatment. In such cases, the veterinarian will stabilize the dog.

 During this period, they will provide supportive care. The most common form of supportive therapy is blood transfusion. This step is critical for dogs with splenic hemangiosarcoma that ruptured and resulted in internal bleeding.

There are also some novel and holistic treatment options for hemangiosarcoma in dogs. These options are used in conjunction with mainstream treatments to boost their effects or decrease the risk of side effects.

 Popular holistic options are CBD oil and Yunnan Baiyao supplements.

Cortisone Shots for Dogs

When dealing with any type of canine cancer, euthanasia is a legit option

When To Euthanize a Dog With Hemangiosarcoma?

When dealing with any type of canine cancer, euthanasia is a legit option. This is the hardest option for most pet owners. However, in certain cases, it is also the only right choice.

Generally speaking, euthanasia should be considered in the following cases:

  • If the treatment causes severe side effects that affect the dog’s quality of life
  • If the dog is disinterested in food and lacks energy for regular daily activities
  • If the treatment expenses are too high and the owner cannot afford them.

We suggest talking to a veterinarian before deciding on euthanasia. Namely, the vet will explain certain things and help you make an informed decision. 

Here are some of the factors the vet will evaluate when advising you on the right decision:

  • The stage of the hemangiosarcoma tumor
  • The dog's quality of life (whether the dog seems happy, is playful, or has a normal appetite, does it moves on its own, vomit, whether it urinates and defecates without assistance, does it looks like it is in pain).

If the answer to the questions referring to the dog's quality of life is no, you should pursue euthanasia.

 Ask the vet to explain the procedure in detail – that way, you will be familiar with what is going on, and you will have better support for your dog during its final moments.  

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