There are many different kinds of skin tumors, some are serious but most are benign. Most skin growths are likely to be either skin papillomas (i.e. warts) or sebaceous gland adenomas. Skin papillomas are common in dogs but rare in cats. Their cause is unknown, although a viral infection appears to be involved in some cases. These growths can appear as solitary or multiple lumps and characteristically have a cauliflower-like surface. There is no way to prevent them from occurring.
Warts can appear anywhere on the body, especially as pets get older, but they cause few problems and are benign. In those cases where a wart causes a problem (e.g .the pet licks it excessively or it becomes infected), it can be removed surgically without difficulty. Usually, warts are left alone.
Sebaceous gland tumors derive from the sebaceous glands in the skin, which secrete an oily substance called sebum. Sebum keeps the skin soft, pliable, and moisturized. These tumors are considered to be the most common kind of skin tumor in dogs, and are often confused with warts since they are similar in appearance. Like papillomas, sebaceous gland tumors are common in dogs but rare in cats. They usually appear after nine to ten years of age, and there appears to be a predisposition in cocker spaniels as well as poodles, Boston terriers, Kerry blue terriers, beagles, dachshunds, Norwegian elkhounds and basset hounds. Sebaceous gland tumors are usually not surgically excised unless they too cause problems.
As a rule of thumb, all growths should be checked out by your veterinarian to ensure that they are not malignant.
Reprinted with permission from www.animalhealthcare.ca