Fibrosarcoma in Dogs

icon May 14, 2024

In this comprehensive guide, we will explore the causes, symptoms, diagnosis, treatment options, and prognosis associated with fibrosarcoma in dogs.

What Is Fibrosarcoma in Dogs?

Fibrosarcoma is a relatively rare but aggressive type of cancer that can affect dogs. It originates from fibrous connective tissue and can occur in various parts of the body, including the skin, bones, and soft tissues. 

Causes of Fibrosarcoma in Dogs

While the exact cause of fibrosarcoma in dogs is not always clear, several factors such as genetics, environmental factors, and immune system dysfunction may contribute to its development. The precise cause of fibrosarcoma in dogs remains elusive, but the above factors may increase the risk of developing this type of cancer.

What Breed of Dog Has Fibrosarcoma?

Genetics plays a significant role, as certain breeds are more predisposed to fibrosarcoma than others. Breeds such as Golden Retrievers, Labrador Retrievers, German Shepherds, and Boxers have been reported to have a higher incidence of fibrosarcoma. Additionally, exposure to environmental carcinogens, radiation, or trauma may also contribute to the development of fibrosarcoma in some cases.

Signs of Fibrosarcoma in Dogs:

Fibrosarcoma can manifest in various ways depending on its location in the body. Common symptoms may include:

1. Lump or Mass:
One of the most noticeable signs of fibrosarcoma is the presence of a firm, rapidly growing lump or mass under the skin or within soft tissues. These masses may feel fixed to underlying structures and can vary in size.

2. Swelling and Pain:
Fibrosarcomas located near joints or bones may cause swelling, lameness, and discomfort in affected limbs. Dogs may exhibit signs of pain, reluctance to move, or limping.

3. Skin Changes:
Fibrosarcomas that develop in the skin can cause ulceration, redness, or changes in skin texture over the affected area. Persistent wounds or sores that do not heal should be evaluated by a veterinarian.

4. Difficulty Eating or Breathing:
In cases where fibrosarcomas develop in the oral cavity or respiratory tract, dogs may experience difficulty eating, swallowing, or breathing normally. This can lead to weight loss, drooling, or respiratory distress.

Diagnosis of Fibrosarcoma in Dogs

Diagnosing fibrosarcoma in dogs typically involves a combination of physical examination, imaging tests, and tissue sampling (biopsy). Your veterinarian may perform the following diagnostic procedures:

1. Physical Examination:
Your veterinarian will carefully examine your dog, palpating for lumps or abnormalities and assessing overall health.

2. Imaging Studies:
X-rays, ultrasound, or advanced imaging techniques such as MRI or CT scans may be recommended to evaluate the extent of the tumor and its potential involvement of nearby structures.

3. Biopsy:
A tissue sample (biopsy) may be obtained either through fine-needle aspiration or surgical biopsy to confirm the diagnosis of fibrosarcoma. This sample is then examined by a veterinary pathologist to identify cancerous cells and determine the tumor's grade and aggressiveness.

How Fast Do Fibrosarcomas Grow in Dogs?

Fibrosarcomas in dogs can vary in growth rate. They may grow rapidly over a few weeks to months or progress more slowly over several months to years. The growth rate depends on factors such as tumor location, size, and individual characteristics.


Fibrosarcoma in Dogs Life Expectancy

The life expectancy for dogs with fibrosarcoma varies depending on factors such as tumor size, location, grade, and treatment response. With aggressive treatment including surgery, radiation, and chemotherapy, some dogs may survive for several months to a few years. However, the prognosis remains guarded due to the tumor's propensity for recurrence and potential metastasis. Regular monitoring and follow-up care are essential to manage the disease and maintain the dog's quality of life.

How Do You Remove Fibrosarcoma from A Dog?

Surgical removal is the primary treatment for fibrosarcoma in dogs. The procedure aims to excise the tumor with wide margins to reduce the risk of recurrence. Before surgery, imaging tests such as X-rays, ultrasound, or MRI may be performed to evaluate the tumor's extent and plan the surgical approach. During the operation, the veterinarian will carefully dissect around the tumor, ensuring complete removal while preserving surrounding healthy tissues. In some cases, amputation may be necessary for tumors located in limbs to achieve adequate margins. After surgery, the dog may require pain management, wound care, and supportive therapy to aid in recovery. Regular follow-up examinations and imaging studies are essential to monitor for any signs of tumor recurrence or metastasis.

Fibrosarcoma in Dogs: Treatment 

Treatment for fibrosarcoma in dogs depends on various factors, including the tumor's size, location, grade, and extent of spread. Common treatment modalities include:

1. Surgery:
Surgical removal of the tumor is often recommended whenever feasible. The goal of surgery is to achieve complete excision of the tumor with wide margins to reduce the risk of recurrence. In some cases, amputation may be necessary for tumors located in limbs.

2. Radiation Therapy:
Radiation therapy may be used as a primary treatment modality or in combination with surgery to target any remaining cancer cells and reduce the risk of local recurrence. Advanced techniques such as stereotactic radiation therapy (SRT) or intensity-modulated radiation therapy (IMRT) may offer precise delivery of radiation while sparing surrounding healthy tissues.

3. Chemotherapy:
Chemotherapy may be recommended for dogs with aggressive or metastatic fibrosarcoma to slow tumor growth, alleviate symptoms, and improve quality of life. Various chemotherapy drugs may be used alone or in combination, depending on the individual case.

4. Immunotherapy:
Emerging therapies such as immunotherapy aim to harness the dog's immune system to target and destroy cancer cells. These treatments may be used in conjunction with traditional therapies to enhance their effectiveness.

5. Palliative Care:
In cases where the tumor is inoperable or metastatic, palliative care focuses on managing pain, controlling symptoms, and improving the dog's quality of life through medications, physical therapy, and supportive care.

Prognosis for Dogs with Fibrosarcoma

The prognosis for dogs diagnosed with fibrosarcoma varies depending on several factors, including the tumor's size, location, grade, and the effectiveness of treatment. Generally, fibrosarcomas are considered locally aggressive tumors with a moderate to high risk of recurrence, especially if not completely excised surgically.

Surgical removal with wide margins offers the best chance for long-term survival, but even with aggressive treatment, some dogs may experience local recurrence or metastasis (spread to other organs). Regular follow-up examinations, imaging studies, and monitoring for signs of recurrence are essential to detect any tumor regrowth or metastatic disease early.


Fibrosarcoma is a challenging diagnosis for dog owners and veterinarians alike. Early detection, accurate diagnosis, and timely intervention are crucial for improving treatment outcomes and maximizing the dog's quality of life. While fibrosarcoma remains a formidable adversary, advances in veterinary oncology continue to offer hope for better treatment options and improved survival rates for affected dogs. If you suspect your dog may have fibrosarcoma or notice any unusual lumps or symptoms, it is essential to consult with your veterinarian promptly for proper evaluation and management.

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