Chondrosarcoma of the Nasal and Paranasal Sinuses in Dogs
A chondrosarcoma (CSA) is the second most common primary tumor in dogs, accounting for ten percent of all primary bone tumors. This is a malignant, invasive and fast spreading tumor in dogs. A CSA of the nasal and paranasal sinuses arises from the mesenchymal tissue, a connective collagenous tissue that is found throughout the body, and metastasizes to other parts of the body, including the nasal bones. It usually occurs on one side of the nasal cavity and extends to the other side over time.
Breeds that have been reported to be predisposed to nasal tumors are German short-haired pointers, German shepherds, keeshonds, basset hounds, collies, old English sheepdogs, Shetland sheepdogs, and Airedale terriers. Dolichocephalic breeds are at higher risk than brachycephalic dogs, males are more predisposed than females, and older dogs are more likely to be affected. In addition, it is believed that animals in urban areas may be more at risk for developing nasal tumors than animals in rural areas. The average age reported is seven years and older.
Symptoms and Types
- Intermittent unilateral or bilateral nose bleed and/or discharge of pus containing material
- Sneezing and difficult breathing (dyspnea)
- Reverse sneezing
- Epiphora (increased tear production)
- Facial deformity
- Unilateral or bilateral obstruction of nasal air flow
- Bad breath (halitosis)
- Poor appetite, weight loss
- Seizures with brain involvement
The exact cause is still unknown but because there is some anecdotal evidence that urban animals are at higher risk or nasal tumors, suggesting an association with pollution.
Your veterinarian will need a complete background medical history leading up to your dog's disease symptoms. Routine blood tests include a complete blood count, biochemistry profile, urinalysis and platelet count. The results may show normal levels. Your veterinarian will also examine the blood samples for evidence of fungal or bacterial infections. Aspergillus is sometimes found in dogs with nasal tumors.
Radiographic studies can be helpful in confirming the diagnosis, but even this type of diagnostic method is challenging. Computed tomography (CT) scans and magnetic resonance imaging (MRI) will often produce a more substantial image of the extent of invasion. An endoscope -- a tubular device with an attached camera that allows for a closer look at the diseased area -- can also be used examine the internal structure of the nasal canal, and may also be used to collect tissue specimens for biopsy, but because of the small space, this can be difficult. Other methods for collecting tissue and fluid samples may be employed, including fine needle aspiration, and suction. Biopsy is the only way to conclusively diagnose nasal cancer.
Your veterinarian may also take radiographs of other areas of the body to evaluate if metastasis is taking place.