Chondrosarcoma in Dogs; Types and Treatment

Chondrosarcoma is a malignant tumor that arises from cartilage cells. The tumor occurs as a large, firm swelling inside the cartilage. Cartilage is the connective tissue that suspends bones together and gives joints smooth flexibility. Chondrosarcoma is the second most common bone cancer in dogs.

Clinically affected dogs usually present with multiple soft-tissue masses in the affected area with regional swelling.

Chondrosarcoma can occur in any dog and there is no preference over male or female dogs.

However, large breed dogs are more susceptible and can include:

• Boxers
• German Shepherds
• Golden Retrievers

Major types of Chondrosarcoma in Dogs

Nasal and Paranasal Sinus Chondrosarcoma

Nasal and paranasal sinus chondrosarcoma are slow growing, progressive, invasive tumors of the nose, nasal cavity and surrounding communicating recesses that can occur in dogs.

As with most tumors, the cause is unknown. These tumors are seen more commonly in dogs than cats and are seen in all ages; however, they are most common in middle aged animals. Chondrosarcoma tends to develop at a younger age than other nasal tumors. There are no breed predilections

Symptoms

Symptoms of nasal and paranasal sinus chondrosarcoma in dogs may include:

• Nasal discharge
• Epistaxis (bleeding from the nose)
• Epiphora (tearing from the eyes)
• Sneezing
• Halitosis (bad breath)
• Anorexia
• Facial deformity
• Exophthalmia (bulging eye)
• Seizures (secondary to aggressive tumors invading the brain)

Treatment

Trestment options and process include ;

• Surgery in combination with radiation therapy
• Radiation therapy
• Chemotherapy
• Antibiotic therapy may be helpful in controlling secondary infection
• Anti-inflammatory drugs may help as temporary symptomatic therapy if more aggressive treatment is not pursued

Chondrosarcoma of The Ribs

Rib tumors are uncommon in dogs. The most common reason for presentation is a palpable mass, although occasionally dogs will present with either lameness or respiratory difficulties.

Thoracic CT scans are recommended to determine tumor location, the extent of the tumor, and for surgical planning.

Treatment and Prognosis

Treatment would include;

Chest wall resection and reconstruction is recommended for dogs with rib tumors. Six, and may be more, ribs can be resected without adversely affecting ventilatory function. Chemotherapy is also recommended for dogs with rib tumours.

The prognosis for dogs with rib chondrosarcoma is very good. Local recurrence is uncommon (17%), but significantly more likely following incomplete excision. The metastatic rate is low with up to 17% of dogs reported to develop metastatic disease.

Chondrosarcoma of Limb

This form of cancer also affects the limbs, with a resulting weakening in the structure of the bone due to the invasive tumor. Fractures of the bone are common.

Large dog breeds are at higher risk, as well as older dogs.

Symptoms

• If tumor is affecting leg, lameness will be observed
• Pain in affected limb
• Fracture in the bone of the affected limb

Diagnosis

X-rays, computed tomography (CT) scans, nuclear bone scans, and radiographic scans will usually be helpful in diagnosing the stage and type of the tumor. Bone scans may show involvement of soft tissue and adjacent bones

Treatment and Prognosis

This is highly aggressive and life-threatening tumor, which requires prompt treatment. Amputation or limb salvage is usually recommended in cases where there is no metastasis (spreading) of the tumor in the affected limb.

Long-term survival appears to be related to having no metastasis of the cancer  (hasn’t spread) and having the affected limb amputated. Unfortunately, if the cancer has spread beyond the limb, survival rate declines.

Oral Chondrosarcoma

Mouth cancer (oral chondrosarcoma) is an oral form of bone cancer that causes neoplastic tumors in the cartilage.

While oral chondrosarcoma may be rare, it seems to be on the rise, with an increase of about 30% in the numbers diagnosed in the past ten years. The cause of this increase is unknown, but veterinary medical professionals believe it is a combination of longer lifespans of dogs, and exposure to toxic chemicals.

Primary oral chondrosarcoma is aggressive but moves slowly. Secondary oral chondrosarcoma is most often an aggressive fast mover, but this can vary depending on the area it spread from and how far advanced the disease is.

Symptoms

Symptoms may include;

• Large and hard mass in or around the mouth or nose
• No pain
• Coughing
• Sneezing
• Drooling
• Bad breath
• Difficulty swallowing
• Weakness
• Deformity of the face

Treatment and Prognosis

At this time, the only effective treatment available is surgery to remove the tumor and any questionable areas around the tumor. Oral chondrosarcoma does not respond to chemotherapy and radiation is only slightly effective, although there have been some cases of radiation therapy that are curative. The best choice remains to be surgery, and it is not always a permanent cure because oral sarcoma has a tendency to return.

Since chemotherapy and radiation are not good choices for treatment, the prognosis for oral chondrosarcoma is not very good. Surgery can remove any visible tumors, and if the disease has not spread. If the disease has spread, your dog may not have much more time and the best choice is to provide rest and pain medication to keep him comfortable as long as possible.