Finding any sort of lump or bump on your pet can be scary. While it is always a good idea to have worrisome lumps checked out, keep in mind that not all lumps are tumors and not all tumors are cancerous.
Tumors are abnormal growths of body tissue and they can either be classified as cancerous (malignant) or non-cancerous (benign). Cancerous tumors can spread at a rapid rate and can metastasize to other areas of the body. For more information, see the Cancer section.
Benign tumors are less serious as they generally stay in one place and do not have the ability to metastasize to other areas of the body. However, some benign tumors can grow to a very large size. If benign tumors like this are left untreated they can eventually cause serious complications, such as interfering with motion or breathing.
The most common type of benign tumor is a lipoma, which is composed of fatty tissue. Usually found under the skin, these growths are painless and in many cases completely harmless to your pet. They are associated with high-fat, commercial diets. The preventative solution, though, is NOT to feed your pet one of the “low fat” commercial pet foods on the market, as these can cause all kinds of other serious deficiencies and illnesses. The best way to prevent tumors of all kinds is to feed your pet a natural and well-balanced, raw diet. 
Including digestive enzymes also helps. See the diet section for more information.
Take any lump on your pet’s body seriously. See a holistic veterinarian. Whether the lump is benign or malignant, your holistic veterinarian will help you to decide what to do next. Odds are, the tumor will be a lipoma and you may not have to do anything other than improve your pet’s nutrition with a raw diet.