The nucleus pulposus is located in the upper part of the unilateral breast and is a chronic condition that occurs in women of childbearing age who are physically weak. When they first appear, they are often found in the upper part of one breast, either one or several at the same time, varying in size from the size of a plum to a small plum, with a smooth, hard, well-defined surface that can be pushed and is not painful to touch. As time goes by, the nucleus gradually grows and becomes painful to the touch, with a soft texture. Once you find a nucleus, you should go to the hospital for treatment in a timely manner so that you don’t miss the best time for treatment.