Cutaneous Squamous Cell Carcinoma in Dogs
The epidermis, or skin, consists of several layers. The outer layer is made up of scale like cells called the squamous epithelium. This layer of tissue covers the surface of much of the body, and lines the cavities of the body. A squamous cell carcinoma is a type of cancer that originates in the squamous epithelium. It may appear to be a white skin mass, or a raised bump on the skin. Often the raised mass will necrotize in the center and ulcerate, with occasional bleeding.
As carcinomas are characteristically malignant and particularly invasive, it is essential to have this form of skin cancer diagnosed and treated without delay. Cutaneous squamous cell carcinomas are typically fast growing tumors that get bigger with time and resist healing. If the ulcers are diagnosed before they have had an opportunity to become malignant, this condition may be treated effectively in some cases.
Squamous cell carcinomas are seen more in dogs that live at high altitudes and in dogs that spend a lot of time in the sun. Scottish terriers, Pekingese, boxers, poodles, Norwegian elkhounds, dalmatians, beagles, whippets, and white English bull terriers seem to get this kind of skin cancer more that other breeds of dogs. Large breed black dogs are more prone to squamous cell carcinomas on their toes than other types of dogs, and dogs that have light colored skin and hair are more prone to this type of skin cancer than other types of dogs. As with most forms of carcinoma, cutaneous squamous cell carcinoma is most commonly seen in older dogs.
Symptoms and Types
- A crusty or bleeding sore on the skin that does not go away with antibiotics or creams
- Sores that do not heal for several months
- Sores in areas where the hair is white or light colored
Growths or Tumors
- White colored growth of skin; mass
Growths in areas where hair is white and skin is light colored
- Sores or growths may be found anywhere
- Usually there is just one growth or sore
- Common locations are the nose, toes, legs, scrotum or anus
- Long term exposure to sunlight/UV rays
You will need to give your veterinarian a thorough history of your dog's health, onset of symptoms, and possible incidents that might have precipitated this condition, such as a recent flea infestation that would have left sores from vigorous scratching. Once this history has been detailed, your veterinarian will conduct a thorough physical examination on your dog, paying close attention to any growths on the skin or any sores that have not healed in several months. Your dog's lymph nodes will be palpated to determine if they are swollen, an indication that the body is fighting an invasive disease or infection, and a sample of lymph fluid will be taken for laboratory analysis. The presence of cancerous cells in the lymph glands will be indicative of metastasis through the body. Basic laboratory tests include a complete blood count and biochemical profile to confirm that your dog's organs are functioning normally.
Because carcinomas are characteristically malignant and metastasize quickly, your veterinarian may also order x-ray images of your dog's chest and abdomen so that a visual inspection can be made of the lungs and organs. Likewise, if your dog has a tumor on one of its legs, your veterinarian will want to take x-rays of the leg to see if the tumor has spread to the bone underneath it.
Standard biopsies will be taken of the growth or sore. This is the best way to determine exactly what kind of tumor your dog has.