Chondrosarcoma (Tumors of the Larynx and Trachea) in Dogs

Chondrosarcomas are slow growing malignant cancers which can sometimes develop in the larynx or trachea of dogs. These tumors can interfere with the animal's ability to eat and to breathe, as well as having the potential to spread to other areas of the body. Removal of the tumor is usually recommended, along with a wide-margin resection. This excision is often followed by radiotherapy to ensure that there is no spread to other organs or reoccurrence of the original tumor.

Chondrosarcoma is a slow growing malignant cancer which can sometimes be found on the larynx or trachea in dogs. Early diagnosis and removal of cancerous tissue results in the best prognosis for this disease.

The symptoms that indicate a chondrosarcoma located in the larynx or trachea are due more to the physical placement of the tumor than its cancerous nature. Symptoms to be alert for include: 

• Blue tinge to mucous membranes or gums 
• Change in voice 
• Collapse
• Coughing
• Difficulty breathin
• Drooling
• Harsh, noisy breathing 
• Inability to exercise 
• Loss of voice 
• Panting 

Types

Other types of  cancerous tumors can occur on the canine larynx or trachea that would cause similar symptoms. These can include:

• Laryngeal oncocytomas - Large solitary tumors that are located in the wall of the larynx, they can be quite large but are not generally aggressive and rarely metastasize
• Osteosarcoma - Although osteosarcoma tumors can be found on the larynx, it is very rare
• Extramedullary plasmacytomas - This type of tumor is occasionally found in the larynx but is more common in the gastrointestinal tract
• Squamous cell carcinoma - These tumors can form on either the larynx or the trachea; squamous cell carcinomas have a higher probability of moving into the lymph nodes
• Mast cell tumor - Although mast cell tumors are usually found on the skin, they have been known to grow on the larynx as well

Chondrosarcomas can either be formed in the bone or formed in the membrane that encloses the bone. Once formed, the sarcomas can move with the bloodstream to any part of the body, including the larynx or trachea. Medium to large dogs are more likely to acquire these tumors, usually after they have reached 6 years old. Chondrosarcomas are malignant and should be removed as quickly a possible to prevent the cancer from metastasizing in the liver, lungs, kidneys, or heart.

Your veterinarian will want most likely start with a physical examination of the masses or lesions on the larynx or trachea and get a tissue sample so that it can be more closely examined to determine its makeup. A complete blood count, biochemistry profile, and urinalysis will also be obtained in order to expose any underlying or concurrent diseases or conditions.

Depending on the size and the placement of the tumor, the veterinarian will generally use either a needle aspiration or full excision technique to take a sample of the affected tissue. The sample will then be examined under a microscope, using a technique known as cytology. X-rays will be completed to look for evidence of cancer on the skeletal system as additional fibrosarcoma tumors, which have a propensity for invading nearby bones. Testing of the lymph nodes, usually by needle aspiration, will also occur to determine if the cancer has metastasized. If the tumor was excised in order to biopsy it, the edges would also be checked at this point to ensure the surgeon got the entire tumor.

Treatment  of sarcomas usually begin with the removal of the tumor itself as well as excising any extensions into surrounding tissue and bone. With chondrosarcomas, this may necessitate removing a large portion of the jaw bone if a spread is noted or suspected. If the tumor and all affected tissues are cleanly and entirely removed and if the cancer has not already metastasized, the prognosis for this treatment is effective in extending survival rates by a year or two.

It is still sometimes recommended that the area is treated with radiation, particularly in the case of tumors on the larynx, as this may preserve the functionality of the larynx. Radiation may also be attempted if the tumor is inoperable because of size or position. Chondrosarcomas are somewhat resistant to both traditional chemotherapy and radiation therapy, so they are only rarely considered as a treatment option, although these treatments may occasionally help to prevent metastasizing of the cancer cells.

Prognosis of chondrosarcoma on the larynx or trachea depends on if the cancer has spread beyond that tumor, and if so, where has it spread to. You will need to examine the site of the tumor regularly for swelling, bleeding or pus. Keeping the recovering patient in a calm and quiet environment will help speed healing, as will having appropriate food and water within easy reach of them.  Specialized feeding and care instructions may be given by your veterinarian to facilitate healing to the excision.