Lipomas are fatty cell tumors that are quite common in dogs. They usually show up in older dogs but we have seen them in puppies as young as 5 or 6 months on occasion. One of the younger dogs we saw did have the malignant form of this tumor which is very rare. For the most part these are benign tumors that do not cause problems. We usually aspirate (draw up some of the lump through a needle) and examine the cells from these tumors to confirm that they are just lipomas. We remove them only if they are causing problems with movement or the owners feel the need to remove them for cosmetic reasons.