Skin Cancer In Dogs

Cancer is actually caused by damage to the DNA. Under normal circumstances the body is able to repair DNA damage, but when the damage isn’t repaired the cells begin to behave abnormally causing out-of-control growth leading to cancer formation. Skin cancer is the most common cancer in dogs. Skin cancer usually occurs in dogs that are middle-age, which is 6 to 14 years old. Of course it can happen in younger dogs too. Many tumors can be benign which means they are of no harm to the dog, it is very important to make sure a malignant tumor isn’t mistaken for a benign tumor. Benign tumors are slow growing and don’t change much over months or even years. Malignant tumors are more likely to grow quickly and have ill-defined margins.

Skin cancers can be divided into four categories: epithelial tumors, mesenchymal tumors, round cell tumors, and melanomas. Epithelial tumors involve the skin itself, glands in the skin or hair follicles. Mesenchymal tumors are tumors from cells that support the skin such as fat, connective tissue, blood vessels, or nerves. Round cell tumors appear as round cells under the microscope. Melanoma tumors occur in the cells that provide pigment in the skin.

The cause of skin cancer is unknown, but exposure to the sun has increased a higher incidence of cancer. Boxers, Bassett Hounds, Scottish Terriers, Bull Mastiffs, Kerry Blue Terriers, and Norwegian Elkhounds have higher incidences of skin cancer leaving scientists to believe that there is a genetic basis for certain types of cancers. A dog that is light-colored with a thin hair coat that spends a lot of time in the sun has a higher risk of developing cancers.

Most skin cancers appear as a lump on or just below the skin or as a sore that just doesn’t heal. Dogs with skin cancer may experience discomfort or itchiness because of the cancer, causing them to scratch or bite at the affected area. There may be redness of the skin or the skin may be flaky. Symptoms vary depending on the location of the tumor and the degree of development. Dogs may experience a loss of appetite, vomiting, diarrhea, lethargy, coughing, labored breathing, or delayed wound healing.

If you notice anything abnormal on your dog’s skin, bring him/her to your veterinarian. Some lumps can be benign, but you need to have it checked out to know for sure. Your veterinarian will do a cytology or biopsy of the lump. Cytology means looking at the cells from the fluid in the lump under a microscope. A biopsy is actually removing a piece of the lump to look at under the microscope. If the tumor is malignant then your dog’s treatment can consist of surgery, chemotherapy, or radiation.