Haemangiosarcoma is a condition that affects the cells in a dog's blood vessel. It is a very aggressive form of cancer and it's considered a serious disorder because the tumours form in a dog's blood vessels which means they are often full of blood and when they rupture, it can lead to both excessive external and internal bleeding. There is a form of haemangiosarcoma that affects a dog's skin which although nasty, is not as serious as when the cancer takes hold in a dog's blood vessels.

Haemangiosarcoma can take hold in just about any part of a dog's body where blood vessels are found which in short means anywhere. However, the most common place for the cancer to take hold is as follows:

• In a dog's skin
• In soft tissue
• In the liver
• In the spleen - this is the most common site for the tumours to first develop

Because the tumours are so malignant, they can quickly spread to other parts of a dog's body and this includes to the following organs:

• Brain
• Lungs
• Heart
• Spleen
• Kidneys

The cancer can also spread very quickly to a dog's skeletal muscles and bones because it is so aggressive by nature. Vets classify this type of cancer as either being dermal, hypodermal/subcutaneous and visceral.

Dermal Hemangiosarcoma Explained

When a dog develops haemangiosarcoma of the skin, it is possible to surgically remove the tumours and the prognosis is generally good with dogs making a full recovery after the procedure. The symptoms of there being something wrong include the following:

• Skin is quite red or has a black growth on it

The condition is often associated with exposure to the sun and the tumours tend to form on parts of the body where the hair is the sparsest which is typically on a dog's abdomen. It can also take hold on any areas where the coat hair is white.

The breeds most at risk of developing this type of haemangiosarcoma include the following:

• Dalmatians
• Pit Bull Terriers (Banned Breed in the UK)
• German Shepherds

Sadly, on occasion the cancer will spread to internal organs which is why it's so important to have the tumours removed sooner rather than later as soon as a correct diagnosis has been made.

Subcutaneous (hypedermal) Hemangiosarcoma Explained

When a dog develops this form of the cancer, all too often the top layers of their skin seem perfectly normal. The problem is found under the skin which develops a red blood growth that's dark in colour. Sadly, in a high percentage of cases the cancer spreads quickly to a dog's internal organs which means the prognosis is never good.

Visceral Hemangiosarcoma Explained

This form of the cancer affects a dog's spleen which is the large organ found in a dog's abdomen. However, although not an essential organ, the spleen does play an important role in that it affects the function of blood and lymph nodes. The trouble starts when any growths whether benign or malignant rupture and break which results in profuse bleeding. A vet might recommend removing the spleen which would stem the bleeding, but it does not mean the cancer would not spread to other parts of a dog's body. Unfortunately, around a quarter of dogs diagnosed with this form of haemangioscarcoma have also developed the heart-based form of the cancer which is short means the prognosis tends to be very poor.

Visceral Hemangiosarcoma Explained

This form of the cancer attacks a dog's heart and therefore it is a life-threatening condition. Much like haemangiosarcoma of the spleen, if any tumours rupture, they cause excessive bleeding in the pericardium which is the sac that encloses the heart. This in turn means a dog's heart is unable to function and pump blood as it should which is a condition called pericardial effusion. When a dog suffers a pericardial effusion, they need to be treated as a matter of urgency before any other procedure can be undertaken and again the prognosis is never good.

The Causes

As previously mentioned, haemangiosarcoma of the skin typically develops because of exposure to sunlight. However, when it comes to the other forms of this aggressive, malignant cancer, the causes remain unknown. With this said, it has been found that in people the causes are thought to be exposure to certain types of chemicals and toxins which includes things like vinyl chloride and as such a lot of research is being carried out to determine just what triggers this form of cancer. In dogs, research has suggested that there could be a genetic link because some breeds are more predisposed to developing the condition than others.

Breeds Most at Risk

It has been found that certain breeds are more at risk than others of developing the condition in any of its forms. Dogs between the ages of six and thirteen years appear to be the most at risk and medium to larger dogs seem to be the most affected by haemangioscarcoma. The breeds most at risk are as follows:

• German Shepherds
• Golden Retrievers
• Labrador Retrievers
• Boxers
• Dobermans
• English Setters

The most common site on a dog's body where the cancer first takes hold tends to be the spleen. However, other locations it can also take only as a primary site include the following bearing in mind that it can start anywhere on the body where there are blood vessels:

• Heart
• Skin
• Lungs
• Liver
• Bone

Symptoms to Watch Out For

The problem with spotting signs of there being something wrong is that most of the tumours develop on a dog's internal organs which means the symptoms are hard to see until the cancer has spread to other parts of the body. The first signs of a problem usually occur when a tumour ruptures which leads to excessive bleeding as such the onset of the problem appears to be sudden and therefore unexpected. However, the most common sign of a problem is when a dog has a lump under their skin. Other symptoms could include the following:

• Visible bleeding - nose bleeds
• Lethargy
• Easily tired
• Weakness for no apparent reason
• Pale gums
• A difficulty breathing
• Swollen abdomen
• Seizures
• Anaemia
• Abnormal heart rhythms
• Collapse
• Depression

Diagnosing the Problem​

A vet would need to have a dog's full medical history and they would need to carry out a full physical examination which would include looking at the following:

• A dog's mucous membranes - for signs of anaemia
• A dog's abdomen - to see if there is any swelling
• Aspirating fluid from a dog's abdomen - to determine if it contains blood and to see if it clots correctly
• A complete blood count
• A chemistry panel
• A urinalysis
• X-rays of chest and abdomen
• A biopsy of a tumour which is challenging as there tends to be many of tumours

Treatment Options

Treating the condition depends on where the tumours have formed, but when it's on a dog's skin, the prognosis is a lot better than when it's elsewhere on their bodies because they can be surgically removed. If the tumours have penetrated deeper into a dog's skin or muscle tissue, a vet might recommend chemotherapy or radiotherapy to ensure a more effective treatment of dermal haemangiosarcoma.

Should a dog be diagnosed with a visceral type of the disorder, a more aggressive approach to treatment would be necessary, but the prognosis is never that good. If a tumour is small, a vet might be able to surgically remove a dog's spleen if the tumour is located there. Tumours found around a dog's heart, if still small, could also be surgically removed which may prolong a dog's life a little. However, surgery alone would not be enough because the cancer is so aggressive and it may have already spread to other parts of the body. As such, the standard treatment for haemangiosarcoma is both surgery and chemotherapy.

The Prognosis

As previously mentioned, the prognosis for dogs suffering from haemangiosarcoma is never good more especially if any internal organs have been affected. As such, once a diagnosis has been confirmed, sadly most dogs succumb to their symptoms around 2 months later. If the cancer has not spread and dogs have been given chemotherapy which they have responded to well, owners can expect dogs to live for another six to ten months. Should a dog just be suffering from the dermal form of haemangiosarcoma, once treated a dog's average life span after tumours have been surgically removed is around six months.

Where the spleen is involved, dogs don't survive for very long once the spleen has been removed, but if the tumour has not ruptured, the prognosis tends to be that much better. Sadly, a blood disorder is typically associated with haemangiosarcoma called disseminated intravascular coagulation or DIC for short and it's where blood clots inside blood vessels which can prove fatal.