A small round lump inside the breast that slides without pain may be a benign breast lesion, such as breast hyperplasia, breast fibroma, or breast lipoma. 1. Breast Hyperplasia: Breast Hyperplasia is a common benign breast disease in clinic. 30~50 years old women are easy to get breast hyperplasia. An imbalance in the ratio of estrogen to progesterone may lead to abnormal endocrine function in women, causing breast hyperplasia. 2. Breast fibroma: Breast fibroma has a higher incidence in women aged 20~25. Pregnancy and drug stimulation are common causes of breast fibroid. 3. Breast Lipoma: This is a benign tumor of the breast composed of mature fat cells. The development of this disease may be related to long-term alcoholism, abnormal fat metabolism and other reasons. If you feel a small round lump inside your breast, it is recommended to go to the breast surgery department of the hospital to improve molybdenum target, breast ultrasound and other related examinations, in order to clarify the cause of the disease and receive treatment for the cause.