ALL DEFINITIONSBreast LumpDefinitionA breast lump is a mass or growth in the breast. It can be painless or painful, and may be accompanied by other symptoms such as nipple discharge or changes in the size or shape of the breast. Most breast lumps are benign. Related SpecialistsShowing 3 of 21Elizabeth BergerMD, MSBarbara A WardMDLaura SheimanMDMore Related Specialists