Tumors are cancerous growths. They may be found on the surface of a bird's body or in the internal organs. Veterinary examination of any growth or lump is highly advised as tumors may grow rapidly or spread.
Lipomas are fatty tumors that affect a variety of pet birds. These are typically benign fatty growths found under the skin. It is classically considered to have both a nutritional and genetic factor for development.
Xanthomas are discrete masses or diffuse, thickened areas of skin that are yellow-orange and dimpled in appearance. They are accumulations of fat and cholesterol and are most commonly found in cockatiels and budgies (and they are more often found in females).