Lipomas are benign fatty tumors and can appear almost anywhere on a dog's body. They're most common in middle-aged and older dogs; overweight dogs are also more prone to them. Lipoomas typically aren't painful but can sometimes grow very large. Most vets don't like to remove them because removal of a lump for cosmetic reasons doesn't warrant the inherent risks associated with surgery. However, if the lipoma interferes with the dog's movement or comfort, they should be removed. Lipomas on any joint, including the knee, can be surgically removed.
Always take your dog to the vet if you see a lump or skin growth. While lipomas are rarely problematic, all lumps and growths need to be assessed to make sure they're not malignant. If a lipoma needs to be surgically removed, it is easier (and often cheaper) to do this when it's still small. Your veterinarian can, in most cases, tell whether a lump is a benign lipoma instead of a malignant tumor simply by feeling it. If there is any question about the composition of a lump, she will do a fine needle aspirate to draw fluid from the lump and look for abnormal cells. If the material inside is too dense to be drawn through a needle, she will either do a tissue biopsy or remove the entire tumor and have a laboratory provide a detailed pathology report. Often a veterinarian will suggest a "two for one" deal for lipoma removal. If the dog needs other elective surgery, such as a dental cleaning, the lipoma can be removed at the same time. This cuts down on the number of times the dog needs to be anesthetized (surgery is harder on older dogs).
Surgical Removal of Lipomas
Usually your veterinarian can remove the lipoma. However, if a tumor involves a complex joint like the knee or has been allowed to grow large and is invading the structure of the joint, she may refer you to a board-certified surgeon. Lipomas are usually located just beneath the skin, although they may have a thin sheath of muscle covering them. Once the dog is sedated, the area is shaved and the vet makes an incision with a scalpel or laser. The lipoma is then surgically removed with a scalpel. If there are any indications it may contain malignant cells, a wide margin of tissue is removed from around the margins of the tumor as well. A drain is placed at the deepest part of the removal site and the incision stitched up. The drain should remain in place from 4 to 7 days so that fluid can drain from the incision and must be removed by the vet. It's important to keep the skin around the drain tube cleaned regularly as directed by your vet. The stitches are removed in 10 to 14 days.