Bone Cancer (Fibrosarcoma) in Cats

Fibrosarcoma of the Bone in Cats

Fibrosarcoma is normally a tumor that originates in the soft tissue, a result of abnormal division of fibroblast cells – the cells that are most prevalent in the connective tissue of the body. In some rare cases, a fibrosarcoma tumor originates in the bone, weakening the structure of the bone, and possibly leading to fractures, and even amputation of the limb. In most cases fibrosarcoma of the bone is benign and non-metastasizing, but there are cases where the tumor is malignant and metastasizes throughout the body, into the organs, lymph nodes and skin.

Clinically, fibrosarcoma of the bone is similar to osteosarcoma, a more common form of bone cancer. The main differences are in the make-up of the tumors. Where an osteosarcoma is made up of bone material, a fibrosarcoma is made up of fibrous collagen material. Fibrosarcoma is confirmed when a biopsy of the tumor shows no production of bone material. The rapidly dividing nature of a sarcoma is the real danger, as it invades and threatens the stability of the bone. In general, tumors of the bone are benign, and are frequently misdiagnosed as cysts and muscular problems.

Symptoms and Types

Loss of motion, inability to walk
Mass can be palpated (examined by touch) at the affected bone
Swelling at the site
Pain when area is touched
Fractures of the bone without other evidence of trauma

Causes

The exact cause for a sarcoma of the bone is still unknown.

Diagnosis

You will need to give a thorough history of your cat's health, onset of symptoms, and possible incidents that might have led to this condition, such as any accidents or illnesses. Standard laboratory tests include urinalysis, a complete blood count, and a chemical blood profile. The presence of higher than normal white blood cells can indicate that the body is warding off a diseased condition, and the other tests will show whether the organs are functioning well, but often, laboratory tests will return as normal. Because of the relative rarity of a fibrosarcoma of the bone, unless an x-ray image is taken it may be diagnosed as a cyst or a swelling in the muscle. Therefore, an x-ray examination will be an important factor in the definite diagnosis. X-rays will also help to diagnose the exact location of the primary tumor, as well as detecting whether there has been metastasis to other parts of body. A computed tomography (CT) scan is another useful diagnostic viewing tool that may help in determining the extent of problem.

For a more conclusive diagnosis, a biopsy of the tumor will need to be taken for analysis. A biopsy of the bone is a more invasive procedure than most, but this is the only way to confirm whether a tumor is benign or malignant. Your cat will need to be anesthetized for this procedure.

Treatment

The treatment of fibrosarcoma of the bone usually involves an aggressive surgical approach in which removal of the area around the tumor is attempted, or a piece of the affected bone is removed. In some cases, the affected limb will need to be amputated entirely. A tumor that has already metastasized to multiple sites before diagnosis carries a poor prognosis for recovery. Keep in mind that not all fibrosarcomas are alike. The tumor that is affecting your cat may not have metastasizing properties, and excision of the tumor and surrounding tissue may very well resolve the problem.

Living and Management

After the initial treatment, a follow up checkup will be planned to regularly monitor for any re-growth of the tumor or metastasis to other areas of the body. You will need to set up a schedule to visit your veterinarian for routine progress checkups. A full recovery will be dependent on the size and location of the tumor.

After surgery, you should expect your cat to feel sore. Your veterinarian will give you pain medication for your cat to help minimize discomfort. Use pain medications with caution; one of the most preventable accidents with pets is overdose of medication. Follow all directions carefully. You will need to limit your cat's activity while it heals, setting aside a quiet place for it to rest, away from household activity, children, and other pets. You might consider cage rest for your cat, to limit its physical activity. Your veterinarian will tell you when it is safe for your cat to move about again.

It is important to monitor your cat's food and water intake while it is recovering. If your cat does not feel up to eating, you may need to use a feeding tube so that it is getting all of the nutrition it needs to completely recover. Your veterinarian will show you how to use the feeding tube correctly, and will assist you in setting up a feeding schedule. While your cat is in the process of healing, you may set the litter box up closer to where your cat rests, and make it so that it is easy to get in and out of the box.