Tonsil Cancer (Squamous Cell Carcinoma) in Dogs

Tonsillar Squamous Cell Carcinoma in Dogs

A squamous cell carcinoma of the tonsils is an aggressive and metastatic tumor that arises from the epithelial cells of the tonsils. 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. While all types of squamous cell carcinomas are invasive, carcinoma of the tonsils is particularly aggressive.

This type of tumor is highly invasive and local extension into the surrounding areas is common. This tumor also metastasizes to other areas of the body, including the nearby lungs and distant organs. As with other types of squamous cell carcinomas, middle-aged and older dogs are more commonly affected. In this case, the incidence is higher in dogs living in urban areas as compared to those in rural environments.

Symptoms and Types

Cause

• Exact cause unknown
• Ten times more common in dogs living in urban areas than those in rural areas

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, which will include a thorough examination of the lymph nodes in the neck area. Abnormally large lymph nodes are indicative of an immune system response to an invasion, but only a laboratory examination of the lymph node fluid and tissue will show the type of involvement. That is, whether the invasion is viral, bacterial, or cancerous in nature.

After the initial examination, your veterinarian will order routine laboratory tests, including complete blood count, biochemical profiles, and urinalysis. The results of these tests are usually normal in these patients unless some concurrent disease is present. Your veterinarian will take a biopsy from the lymph nodes to be sent to a veterinary pathologist. This tissue sample will be processed and analyzed microscopically for cancerous cells in order to reach a definitive diagnosis. Your veterinarian may also take X-rays of your dog’s skull and thoracic regions to search for evidence of metastasis. Skull X-rays in some patients may show bone involvement — where the tumor has spread into the bone — and thoracic X-rays can help identify the amount of metastasis into the lungs.

Your veterinarian may also take X-rays of your dog’s skull and thoracic regions to search for evidence of metastasis. Skull X-rays in some patients may show bone involvement — where the tumor has spread into the bone — and thoracic X-rays can help identify the amount metastasis into the lungs.