A lump in the breast can be caused by many things but I would advise you to encourage your mother to see her Family Physician so that he/she can examine her breast and perhaps order a Mammogram to find out exactly what is going on. This could be something very simple but it's best to find out for sure.
How are you? How is your mother? Was there a previous injury to breast? Is there a family history of breast cancer? A breast lump is a growth of tissue that develops within your breast. There are many causes of breast lumps. Some of these causes are harmless, while others can be dangerous. Lumps in a woman are often caused by injury, infection, fibrocystic changes, fibroadenomas, cysts and even cancer. It would be best to consult a doctor for proper evaluation of the breast lump.
Take care and keep us posted.