Lipoma. A lipoma is a slow-growing, fatty lump that's most often situated between your skin and the underlying muscle layer. A lipoma, which feels doughy and usually isn't tender, moves readily with slight finger pressure.Lipomas are usually detected in middle age.ipoma. A lipoma is a slow-growing, fatty lump that's most often situated between your skin and the underlying muscle layer. A lipoma, which feels doughy and usually isn't tender, moves readily with slight finger pressure.