Hemangiosarcoma in Dogs: Know the Early Signs

By Clearvoice / June 12, 2018
sick pup with hemangiosarcoma in dogs

Perhaps one of the scariest aspects of Hemangiosarcoma in dogs is the degree to which it can develop. Hemangiosarcoma penetrates the dog’s blood vessels and can appear in any of the tissues in the body that have blood vessels. Therefore, essentially, Hemangiosarcoma can develop in just about any part of the dog’s body.

But learn the early signs and how to fight it below!

What is Hemangiosarcoma in Dogs?

Hemangiosarcoma (HSA), which is also referred to as angiosarcoma or malignant hemangioendothelioma, is a cancer of the blood vessel walls.

Scientifically speaking, the cancer originates in the dog’s endothelium. The endothelium is a term that refers to the upper of tissue that surrounds the dog’s lymph nodes, blood vessels, and heart.

Perhaps one of the scariest aspects of Hemangiosarcoma is the degree to which it can develop. Hemangiosarcoma penetrates the dog’s blood vessels and can appear in any of the tissues in the body that have blood vessels. Therefore, essentially, Hemangiosarcoma can develop in just about any part of the dog’s body.

Furthermore, Hemangiosarcoma tumors are often filled with blood. A ruptured Hemangiosarcoma tumor can lead to internal and external bleeding.

For these reasons, amongst others, a Hemangiosarcoma diagnosis is one that shouldn’t be taken lightly.

Sarcoma in Dogs

The term sarcoma is defined as a malignant tumor of connective or other nonepithelial tissue. Therefore, “hemangio” refers to a tumor of the blood vessels.

Types of Hemangiosarcoma in Dogs

There are three types of canine hemangiosarcoma:

  • Dermal Hemangiosarcoma
  • Subcutaneous Hemangiosarcoma
  • Visceral Hemangiosarcoma (which can be either spleen based or heart-based)

Symptoms of Hemangiosarcoma (HSA)

Each of the three types of hemangiosarcoma has its own set of symptoms that dog owners should be able to recognize in order to act efficiently if they should arise. As we break down each type of hemangiosarcoma tumor, we will discuss specific clinical signs of that particular type of tumor.

With that said, there are several general clinical signs of hemangiosarcoma. The typical symptoms of HSA include:

  • A lump or bump under the skin
  • Lethargy
  • Getting fatigued easier than usual
  • Visible bleeding (such as nosebleeds)
  • Pale coloring or whitening of the gums
  • Sudden weakness
  • Swelling in the abdomen
  • Difficulty breathing
  • Depression
  • Seizures
  • Sudden collapse
  • Abnormal heart rhythms

Dermal Hemangiosarcoma

A dermal hemangiosarcoma tumor appears on the surface of the dog’s skin. Due to its location, when the hemangiosarcoma tumor is classified as dermal, it also falls into the category of being the easiest to remove. Additionally, dermal hemangiosarcoma has the highest potential of making a full recovery.

Symptoms of Dermal Hemangiosarcoma in Dogs

The symptoms of a dermal hemangiosarcoma tumor will often be visually apparent to the dog owner. Dermal hemangiosarcoma tumors will typically develop as reddish or black growths on the outer layer of the dog’s skin.

While there is not a definite cause, dermal hemangiosarcoma tumors are generally associated with sun exposure. Therefore, the tumor will often appear on the areas of the dog’s body that have little to no protection from fur (i.e on their underbelly). Additionally, dogs with short, light hair, dogs that are losing fur, and hairless dogs are more susceptible to developing a dermal hemangiosarcoma tumor.

Subcutaneous Hemangiosarcoma (or Hypodermal Hemangiosarcoma)

Subcutaneous hemangiosarcoma (hypodermal) tumors occur under the top layer of skin (while dermal hemangiosarcoma tumors develop on the surface level). Experts estimate that approximately 60% of subcutaneous hemangiosarcoma tumors spread internally in the dog and can quickly lead to additional, incredibly serious issues.

Symptoms of Subcutaneous Hemangiosarcoma (Hypodermal Hemangiosarcoma) in Dogs

Subcutaneous hemangiosarcoma in dogs typically develops as dark red blood growths under the skin. Hemangiosarcoma tumors occurring on or in the skin will often be able to be seen or felt as a mass or bump.

If the tumor develops under the skin on a bone, it can cause the dog substantial discomfort. The tumor may also rupture easily depending on the location.

Canine Visceral Hemangiosarcoma

Visceral Hemangiosarcomas make up approximately 2% of all malignant tumors diagnosed in dogs. These tumors most commonly affect the spleen and the heart.

Visceral Hemangiosarcoma – Spleen

As we briefly touched on, there are two main types of visceral hemangiosarcoma. One of these types is a visceral hemangiosarcoma tumor of the spleen. Regardless of whether they are malignant or benign, splenic hemangiosarcoma tumors have the tendency to burst and cause internal bleeding which can quickly become life-threatening.

While surgical removal of the spleen (an operation called a splenectomy) is possible, the malignancy of the tumor invasion will still exist. Experts have determined that even with a successful splenectomy, the dog’s median survival time is only 19-83 days.

rottweiler with spleen cancer in dogs

Where is the Spleen

The spleen is located in the dog’s abdomen.

Spleen Function

The spleen is not essential for life. However, it does serve an important function for the dog’s blood and lymph nodes.

Symptoms of Visceral Hemangiosarcoma – Spleen

Symptoms of splenic hemangiosarcoma tumors will often encompass the general hemangiosarcoma signs we mentioned. However, if complications occur, symptoms will be much more extreme.

Ruptured Spleen Symptoms

Furthermore, if the spleen bursts and bleeding occurs, the clinical signs will be much more obvious and will specifically include:

  • Weakness
  • Anemia
  • Collapse (particularly when the bleeding is severe)
  • Gums that appear pale or white

These symptoms may have an incredibly fast onset depending on the degree of rupture and the amount of internal and/or external bleeding.

Visceral Hemangiosarcoma – Heart-Based

The other type of visceral hemangiosarcoma is based in the heart. Comparably to splenic hemangiosarcoma, heart-based visceral hemangiosarcoma is often life-threatening due to rupturing and bleeding.

Additionally, medically speaking, the heart is enclosed in a sack of tissue that doctors refer to as the pericardium. The pericardium can fill with blood if the heart-based visceral hemangiosarcoma bursts and begins bleeding. This causes an exorbitant amount of pressure on your dog’s heart which impairs it from being able to function properly (a condition referred to as pericardial effusion). Pericardial effusion can lead to even more issues.

Symptoms of Visceral Hemangiosarcoma – Heart

While symptoms of hemangiosarcoma will also encompass the clinical signs of heart-based visceral hemangiosarcoma, there are a few specific signs that pet owners should be aware of. These symptoms include:

  • Unexplainable weakness
  • Difficulty breathing/ respiratory issues
  • Exercise intolerance
  • Fluid buildup in the abdomen
  • Loss of appetite
  • Lethargy
  • Weight loss

Additional Hemangiosarcoma Related Issues

In many cases of hemangiosarcoma in dogs, metastasis occurs. In other words, the cancer cells spread and can quickly affect other organs and tissues. Metastasis of hemangiosarcoma often quickly affects the following essential, internal organs and tissues:

  • Liver
  • Lungs
  • Oral cavity
  • Kidneys
  • Muscle tissue
  • Bone
  • Uterus
  • Urinary bladder

Causes of Hemangiosarcoma

Despite thorough and continued research, a definite cause of hemangiosarcoma in dogs is still relatively unknown. Experts suggest that hemangiosarcoma has genetic ties due to certain breeds (such as golden retrievers) being at a higher risk. Additionally, veterinarians believe that environmental factors (such as sunlight) also come into play when determining a cause of the hemangiosarcoma.

Furthermore, hemangiosarcoma in humans is very rare, which is good news for pet owners, but ultimately doesn’t aid in providing information about the disease in their furry companions.

Breeds at Risk for Hemangiosarcoma

  • Golden retrievers
  • Flat-coated retrievers
  • Labrador retriever
  • German shepherds
  • Boxers
  • English setters
  • Doberman pinschers

Diagnosing Hemangiosarcoma

Again, the diagnosis of hemangiosarcoma in dogs will depend on the type of hemangiosarcoma.

Most often, your veterinarian will begin with a basic physical exam of your pup. The exam will include checking the gums for a pale or white coloring which is a telling sign of anemia.

Furthermore, your vet may also do several or all of the following tests in order to provide an accurate diagnosis:

  • Complete blood count (CBC)
  • Urinalysis
  • Chemical blood profile testing
  • Chest x-rays
  • Thoracic radiography test (to determine if the tumor cells have spread to the lungs)
  • Ultrasonograms (to recognize tumors in the liver and/or spleen)
  • Echocardiogram (to be able to recognize any masses in the heart)

Ultimately, in order to make a definite diagnosis, a biopsy will be necessary. However, this can become exceedingly difficult due to the fact that the most accurate results come from a biopsy of the primary tumor. Therefore, when there are multiple tumors present, it can be impossibly hard to determine which is the primary tumor.

brown puppy with hemangiosarcoma dog symptoms of dizziness

Treatment for Hemangiosarcoma in Dogs

Similarly, treatment for hemangiosarcoma in dogs will vary based on the location and type of the tumor.

Dermal Hemangiosarcoma Treatment

Dermal hemangiosarcoma is the best prognosis and easiest treatment of the three types of dermal hemangiosarcoma tumors. Typically, the affected area of skin is removed in a fairly simple surgery. Often times, veterinarians will recommend using chemotherapy in addition to the surgical removal.

Additionally, chemotherapy will help if the dermal hemangiosarcoma was not able to be fully removed or if spread to the subcutaneous tissue under the skin’s surface. Furthermore, some veterinarians may use radiation therapy in order to ensure that the cancer cells have been thoroughly removed.

Visceral Hemangiosarcoma Treatment

Conversely, treating visceral hemangiosarcoma tumors is typically much more challenging and generally doesn’t have a positive prognosis.

While the spleen, as well as tumors surrounding the heart, can be removed, these procedures only help prolong the dog’s life and ease the symptoms of the disease. Unfortunately, even with aggressive chemotherapy treatments, cancer has spread throughout the body.

Commonly, if your veterinarian recommends chemotherapy treatments, it will often be one of the following:

  • Doxorubicin
  • Cytoxan
  • Cyclophosphamide
  • Vincristine

Hemangiosarcoma: A Final Thought

By and large, it is a sad reality that cancer in dogs still remains one of the largest causes of death amongst our four-legged fur babies. Additionally, as time progresses and scientific studies continue improving and enhancing, cancer diagnoses continue to rise.

In fact, an estimated 50% of dogs over the age of ten years old will develop cancer at some point in their lives. While this is in substantial part because due to advancements in science being able to detect the disease, it is also in correlation with the increase of toxins in our pets’ day to day lives.

All things considered, hemangiosarcoma is among the common forms of cancer in dogs and is one that pet owners should be implicitly aware of. Therefore, knowing the signs of the disease can ultimately save your dog’s life.

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