Hi, Thanks for writing in. The breast is a fatty and glandular tissue containing organ. When in the younger age, it contains more glandular component and less fat. As a woman gets older the fatty content increases more than the glandular one. Sometimes, due to hormonal factors, there is development of cysts in the breast. While they are usually soft and slip under the hand on clinical examination there are cysts that can get infected and then become firm and painful. Breast cysts can be usually made out by ultrasound and mammography when done together. A biopsy is a confirmatory test and can cause a small area or scar and fibrosis that appears as a hard lump on healing. It will subside by itself. To confirm the presence of a breast cyst, you can get a repeat breast ultrasound done and this will show a collapsed cyst with scar tissue. Please do not worry.