There are several types of benign (non-cancerous) breast lump, most of which are harmless and are caused by hormonal changes that occur at different times in a woman's life, such as during the menstrual cycle.. Common types of benign breast lump include: Fibroadenoma – a firm lump that moves around easily in the breast and is more common in younger women Breast cyst – a smooth, firm fluid-filled lump most commonly seen in women aged 30 to 60 breast abscess – a painful collection of pus that forms under the skin of the breast, usually as the result of a bacterial infection. Consult Surgeon for further evaluation and treatment...