This bump may represent a small hernia or a lipoma. A hernia is a small defect in the abdominal wall through which internal organs can protrude to the outside. A lipoma is a small collection of fat in the subcutaneous tissue.The best way to differentiate these entities is whether the lump is constant or seems to come and go. Hernias tend to be present at times ( bulging ) and disappear at others were as lipoma is are usually if constant and do not change in size over time. Both of these conditions are not worrisome but it is preferable to be examined by a surgeon.