Chondrosarcoma in Dogs

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.

The condition usually affects adult dogs with an average age of onset at 6 years old. Medium or large breed dogs are believed to be more likely to develop the condition. Chondrosarcoma usually affects the ribs, nasal bones and pelvis. It can also occur in the facial bones, trachea, or metacarpals (digits of the feet). The tumor is capable of metastasizing to the lungs, liver, kidney and heart. Most dogs suffering from chondrosarcoma do not experience pain unless the tumor affects bones or organs near it's growth.

Symptoms of Chondrosarcoma in Dogs

Symptoms of chondrosarcoma vary and will depend on the location of the tumor in the dog's body. Nasal chondrosarcoma may be more easily detected than tumors that occur in other regions of the body. Symptoms of nasal chondrosarcoma may include:

  • Sneezing
  • Bloody discharge
  • Purulent discharge (pus)
  • Difficulty breathing
  • Anorexia
  • Facial deformity

Chondorsarcoma that occurs in the pelvis may cause pain or discomfort that is apparent upon examination of the region. A tumor in the pelvis region may also cause lameness in the hind limbs. Chondrosarcoma that occurs in the ribs may cause a swelling in the center of the chest, where the dog's ribs join. Spinal chondrosarcoma often shows no visible signs.

If chondrosarcoma has spread to the lungs, the dog may exhibit other symptoms such as:

  • Lethargy
  • Difficulty breathing
  • Shortness of breath
  • Coughing
  • Lameness
  • Painful swelling in all limbs

Diagnosis of Chondrosarcoma in Dogs

A dog suspected of chondrosarcoma will receive a complete physical and orthopedic examination. Laboratory blood work will be done to determine the dog's overall condition and general health. The dog's condition is an important factor when determining the course of treatment for chondrosarcoma.

Tumors of chondrosarcoma are capable of metastasizing to other organs, and a veterinarian will recommend radiographs (X-rays) of the chest and abdomen to determine if metastasizing has occurred. Radiographs, bone scans, or CT scans may be necessary to assess the condition of the affected region. Cancer cells that are present in the blood may concentrate in the lymph nodes. A veterinarian may recommend a fine needle aspiration biopsy of any lymph nodes that appear enlarged in radiograph or ultrasound images.

Treatment of Chondrosarcoma in Dogs

Treatment of chondrosarcoma in dogs must be aggressive. Most dogs are not symptomatic until the advanced stages of the disease. The exact course of treatment depends on the stage of the cancer and the overall condition of the dog. Complete surgical removal of the tumor(s) is usually necessary. Surgery is not necessarily curative, but is aimed at providing relief and extending the dog's life span.

Surgery is most effective if the tumors are local to one region of the body and have not metastasized. A dog recovering from surgical removal may require additional postoperative care. Amputation of a limb or radiation treatments are often necessary even after the removal of the tumor(s). Immunotherapy may be recommended to stimulate the dog's own immune system and destroy the cancer cells. Chemotherapy has not been shown to be effective when treating chondrosarcoma in dogs.