Lipomas are very common, benign growths in dogs. They are seen less frequently in cats.
These growths consist of fat cells and can range in size from very tiny to ten or more inches in diameter. The most common areas to find lipomas are under the skin in the regions of the abdomen and chest. Most lipomas are fairly soft, non-painful lumps just under the skin.
We diagnose a lipoma by taking a sample with a small needle, staining it on a slide, and then looking at the cells under a microscope (a fine needle aspirate). Lipomas are characterized by fat cells with no evidence of infection or other tumor cells. We recommend a fine needle aspirate of any lump you notice on your pet, as microscopic examination is necessary for an accurate diagnosis to help us differentiate benign (non-cancerous) from malignant (cancerous) tumors.
No treatment is necessary for lipomas that remain relatively small and do not bother the animal. Some lipomas can grow large and interfere with movement of a limb, or bother the animal when he or she lies down. In that case, surgical removal is advised. Any lipomas that are growing rapidly should be re-evaluated and another fine needle aspirate performed, or the growth should be removed.