Nose Pad Cancer (Squamous Cell Carcinoma) in Dogs

Squamous Cell Carcinoma of Nasal Planum in Dogs

The epithelium is the cellular covering of all of the internal and external surfaces of the body, protecting the organs, inner cavities and outer surfaces of the body in a continuous layer of multi-layered tissue. The squamous epithelium is a type of epithelium that consists of the outer layer of flat, scale-like cells, which are called squamous cells.

In this case, squamous cell carcinoma of the nasal planum arises from the tissue in the nose pad, or in the mucous membranes of the nose. A squamous cell carcinoma is a malignant tumor of the squamous epithelial cells, but in the case, the risk of malignant metastasis is relatively low. It is often more invasive that metastatic. Exposure to inhaled chemicals increases the risk of nasal tumors, including indoor use of coal, cigarettes, and air fresheners.

This tumor is rare in dogs as compared to cats. There does not appear to be any particular breed, gender or age that is more susceptible, but it is suspected that dogs with larger nasal passages may be at higher risk, and dogs with light pigmented noses are at risk. A lot of time spent in the sun can also increase the risk.

Symptoms and Types

• This tumor progress slowly, often starting as a superficial crust and scab
• Decreased air through the nose (i.e., more mouth breathing)
• Sneezing and reverse sneezing (i.e., sudden, involuntary inward breaths)
• Nosebleeds (epistaxis)
• Nasal discharge
• Swelling of involved area, including swelling of the eye, loss of sight
• Facial deformity
• Excessive tears from eyes (epiphora)
• Neurological signs (from pressure on brain) – seizure, disorientation, behavioral changes

Causes

• Exposure to excessive sun light
• Absence of protective pigment
• Exposure to toxic inhalants

Diagnosis

You will need to give your veterinarian a thorough medical history of your dog's health and onset of symptoms. Your veterinarian will perform a physical examination with full laboratory testing, including complete blood tests, biochemical profiles, and urinalysis. The results of these tests are usually normal in affected patients. While metastasis is rarely seen in the lungs, your veterinarian may take thoracic x-rays to evaluate for metastasis into the lungs. Other conditions your doctor will look for are dental diseases, aspergillosis, bacterial rhinitis, foreign object (such as a plant awn), and parasites (such as mites).

For an appropriate diagnosis to be made, your veterinarian will need to take tissue and fluid samples from the affected area. Your veterinarian will also take samples from the lymph nodes to detect whether metastasis is occurring. Magnetic resonance imaging (MRI) and computed tomography (CT) scans may provide more information about the extent of the tumor, as well as to help in surgical resection of the tumor.

Treatment

There are various surgical modalities available and selection will be based on the location and extent of the problem. Surgery will be conducted to remove the affected tissue along with some margins of the normal tissue, to be certain that all of the affected tissue has been removed. If the tumor is invasive in nature, a deeper surgical resection will be required, followed by radiation therapy. Chemotherapy may also be advised in these patients, though it has not yet been satisfactorily evaluated for this type of cancer. Your veterinarian will consult a veterinary oncologist for the best treatment plan for your dog.

Living and Management

Overall prognosis is good if the tumor is small and superficial. If the tumor is invasive and metastatic in nature, the prognosis will not be positive. The decision to go forward with surgery or chemical therapy will be based on the actual prognosis. In some cases, end of life pain management may be in order. Good nutritional support is essential for these patients to ensure maintenance of body weight and condition.

Always seek advice and instructions from a veterinary oncologist before giving chemotherapy medications, as these drugs are highly toxic to human health. Pregnant women in particular should take extra care while administering chemotherapeutic drugs to their pets. Chemotherapy medications have the possibility of toxic side effects, so your veterinarian will need to closely monitor your dog's stability, changing dosage amounts as necessary.

After surgery, you should expect your dog to feel sore. Your veterinarian will give you pain medication for your dog to help minimize discomfort, and you will need to set up a place in the house where your dog can rest comfortably and quietly, away from other pets, active children, and busy entryways. Trips outdoors for bladder and bowel relief should be kept short and easy for your dog to handle during the recovery period. Use pain medications with caution and follow all directions carefully; one of the most preventable accidents with pets is overdose of medication.

Prevention

If your dog is at increased risk for acquiring this disease, you may take preventive measures by limiting sun exposure, especially from 10:00 am to 2:00 pm. Sunscreens have not been found to be effective for the prevention of this tumor.