Fibrosarcoma of the Bone in Dogs

Bone fibrosarcomas can occur in any breed, any size, any gender, and in any location. Typically, they occur on an extremity or on the mandible or maxilla. Depending on the location, the tumor may be removable. If it is at a location that cannot be removed, there are other therapies that can be administered but may not be a permanent fix. Symptoms of a bone fibrosarcomas can be unnoticeable or can manifest as severe symptoms such as limping or even paralysis.

Bone fibrosarcoma is a type of bone tumor that can develop from fibrous tissues. If your dog seems to be in pain without a known cause or is favoring a limb, take him to his veterinarian for further evaluation.

Bone fibrosarcomas can develop in your dog without you knowing it. Symptoms can be vague but indicators can include:

• Limping
• Trouble getting up
• Slower movements 
• Arthritic type symptoms
• Pain in a specific area
• Stops using affected limb altogether
• Immobilization 
• Paralysis 
• Mass like growth

Types

Fibrosarcomas of bone in dogs can have different places of origin. The tumors can originate directly off the bone, from connective tissues, from blood vessels, and cartilage. Depending on the location of the tumor, it may go by another name or be known by its location.

There is no specific cause of fibrosarcoma development in dogs. Some breeds, sizes, genders, and age groups are more prone to them than others. Fibrosarcomas develop when the body does not realize the cells are abnormal. While the immune system will normally recognize the cells are bad and will destroy them, in this type of situation it doesn’t realize it so the body allows it to develop.

Diagnosis of bone tumors in dogs can be difficult. For a proper diagnosis, your dog will need radiographs and a histopathological examination of the tumor itself. A radiograph cannot always offer a positive diagnosis, only a suggestion that the mass is likely a fibrosarcoma. For a definite diagnosis, a histological examination has to be completed. 

Blood work will be performed to give the veterinarian a broad look as to how the internal organs are functioning and to rule out other possible causes of his symptoms. A complete blood count (CBC) and chemistry panel will provide the veterinarian with needed information for proper assessment of organ function. A packed cell volume (PCV) may also be performed to determine hydration status. 

Other diagnostic tests may be performed as the veterinarian sees fit. She may even have to refer you to a specialized hospital for more advanced testing.

There are not many options regarding the treatment of fibrosarcoma of the bone in dogs. There are the options of chemotherapy, other drugs to be tried, and surgical removal of the affected limb. In cases of bone fibrosarcomas, the drug known as mitoxantrone is commonly used due to its ability to disrupt and break up DNA. 

Radiation is also an available treatment for this condition. In many cases, veterinarians use a combination of chemotherapy, surgery, and radiation to treat the fibrosarcoma.

Amputation is an accepted form of treatment for bone fibrosarcomas. Treatments like radiation and chemotherapy may not work or may not be an aggressive enough form of treatment if the tumor is fast growing. 

Your veterinarian will want to keep a close eye on your dog. She will want to do tests periodically to check his blood chemistry and values. She will be able to monitor him and suggest medications and therapies as his condition changes.

The location of the bone fibrosarcoma will play a large part in your dog’s recovery process. If it is on a limb that can be amputated and it is removed, and if the veterinarian is able to get it all, chance of recovery is good. 

If the tumor cannot be removed, the veterinarian will likely recommend supportive therapies and treatments for your canine’s symptoms. Unfortunately, there is no cure for cancer at this time, but there are constantly new studies and treatments being tried. Just because your dog is diagnosed with a bone fibrosarcoma does not mean it is the end of his life. Many can survive and even thrive even after diagnosis.