Understanding Canine Skin Cancer

Just as humans experience high incidents of skin cancer, canine forms of this disease occur in high rates among dogs. Skin cancer is believed to be the most common cancer found in dogs. The condition is related to the abnormal growth of various kinds of skin cells, including hair follicles, glands, pigment cells, and connective tissues like fat. Dog skin cancer is categorized according to the type of skin cells involved in the disease and the nature of cancer-related tumors. Although any dog can develop skin cancer, some breeds and age groups are more susceptible to certain forms of the disease than others. Understanding characteristics of canine skin cancer as well as guidelines for prevention can help owners make informed choices regarding the disease.

Different Types of Canine Skin Cancer

One of the most commonly diagnosed forms of canine skin cancer is squamous cell carcinoma. There are two varieties of this malignant cancer. Cutaneous squamous cell carcinoma often appears as crusted or raised lesions on the skin of the face, ears and abdomen. It is more common among older dogs and such breeds as Basset Hounds, Standard Poodles, Bloodhounds, Dalmatians, Bull Terriers and Beagles. The subungual form of the disease occurs in the nail bed region, and is found most often in Schnauzers, Kerry Blue Terriers, Standard Poodles, Briards and Gordon Setters. Prolonged exposure to UV radiation is thought to be a main factor in the development of both forms of squamous cell carcinoma.

Another common type of canine skin cancer affects immune system cells called mast cells. They are located primarily in the skin and connective tissue and contain infection-fighting chemicals responsible for inflammation. Mast cell tumors (MCT) are found in the subcutaneous and deep layers of skin, and are considered the most common kind of skin cancer tumors. They vary in appearance, from lumpy to smooth, and often occur in the limbs, trunk and genital areas. Although an exact cause has not been identified, MCTs appear hereditary in Boston Terriers, Boxers, Golden Retrievers, Pugs and English Bulldogs.

Basal cell carcinoma is form of skin cancer typically affecting older dogs, around 6 to 8 years. Basal cell tumors are often identified as firm, isolated and well-defined growths occurring deep within the skin of the affected animal. These slow-growing tumors appear most frequently on a dog's neck, shoulders and head. Prolonged sun exposure is commonly associated with the development of this form of canine skin cancer.

Skin cancer is also categorized according to the type of tumors and skin cells involved in the disease. The four most common types found in dogs are:

  1. Epithelial tumors affect the skin tissue, hair follicles or glands, and are associated with basal cell carcinoma and squamous cell carcinoma.
  2. Melanomas are dangerous tumors involving the cells responsible for pigmenting the skin. They are often identified as oddly shaped and darkly colored lesions on the skin and mouth. Immediate medical attention is recommended to treat this rapidly growing cancer.
  3. Mesenchymal tumors are found in connective tissue like fat and in the nerves and blood vessels. These tumors are not as uniformly round as epithelial growths, and may appear lumpy or odd-shaped. They can develop throughout the body and are often categorized as fibrosarcoma, hemangiosarcoma and lipoma.
  4. Round cell tumors, named for their round appearance under a microscope, include mast cell tumors and plasma cell tumors that affect the skin and mouth.

Canine Skin Caner Prevention

Although the cause of many forms of canine skin cancer remains unknown, owners can help prevent the spread and development of some conditions. To help avoid squamous cell carcinoma and basal cell carcinoma, owners may consider limiting their dog's exposure to the sun. Light pigmented animals are especially vulnerable to the effects of UV radiation. Owners should also examine their pet's skin regularly for any growths, lesions or discoloration. Such symptoms may require immediate medical treatment.

Like people, dogs can develop a variety of different skin cancers. Understanding the disease begins with learning about its different characteristics, and, when possible, knowing how to reduce the risk of your pet developing skin cancer.