Hemangiopericytomas are a type of sarcoma that commonly develops in older dogs, particularly affecting the lower legs and chest. These tumors are typically firm and solitary with irregular borders and are found in the fatty layer beneath the skin. While hemangiopericytomas can invade surrounding tissues, they rarely spread to other parts of the body. In this article, we will explore the causes, symptoms, and treatment options for hemangiopericytomas in dogs.
What Are Hemangiopericytomas?
Hemangiopericytomas are soft tissue sarcomas that originate in the cells surrounding blood vessels. These tumors are more likely to develop in older female dogs and tend to affect breeds such as Siberian Huskies, Irish Setters, German Shepherds, and mixed-breed dogs. These tumors grow slowly and are typically firm with irregular borders, occurring most frequently in the fat layer beneath the skin.
Symptoms of Hemangiopericytomas
The primary symptom of a hemangiopericytoma is the appearance of a firm, solitary mass. These tumors are often located on the lower legs and chest but can also appear in other parts of the body. Some key characteristics include:
- Firm, irregular masses: The tumors are typically firm to the touch with looping, irregular borders.
- Slow-growing: Hemangiopericytomas tend to grow slowly over time.
- Locally invasive: While these tumors rarely spread to other parts of the body, they can invade nearby tissues, making them more difficult to remove completely.
Causes and Risk Factors
Several factors may increase a dog's risk of developing hemangiopericytomas, including:
- Age: Older dogs are more likely to develop this type of tumor.
- Breed predisposition: Siberian Huskies, Irish Setters, German Shepherds, and mixed-breed dogs are particularly at risk.
- Gender: Hemangiopericytomas occur more frequently in female dogs than in males.
Treatment Options for Hemangiopericytomas
The most effective treatment for hemangiopericytomas is complete surgical removal. However, due to the tumor's locally invasive nature, it is crucial to remove not only the tumor but also a wide margin of healthy tissue around it to minimize the risk of regrowth.
- Surgical Removal: The first line of treatment is surgery. Because tumor cells may remain after surgery, removing a wide area of surrounding tissue is essential. If the initial surgery is not thorough, regrowth is common within a year.
- Follow-up Surgery: If the tumor regrows, a second surgery is often necessary to remove the remaining tumor cells.
- Radiation Therapy: In cases where complete surgical removal is not possible, or to reduce the risk of recurrence, radiation therapy may be recommended.
- Chemotherapy: While not as commonly used, chemotherapy may be combined with surgery and radiation to further decrease the likelihood of tumor regrowth.
Prognosis
While hemangiopericytomas are locally invasive and can regrow, they rarely metastasize to other parts of the body. The prognosis depends on how early the tumor is detected and whether complete surgical removal is achieved. Dogs that receive proper treatment, including follow-up surgeries and radiation therapy, often have a good quality of life.
Hemangiopericytomas are a challenging but manageable type of tumor in dogs. Early detection and complete surgical removal are key to reducing the risk of recurrence. If you notice a firm mass on your dog’s lower legs or chest, particularly if they are an older dog, consult a veterinarian immediately for diagnosis and treatment options.