Adolescent girls are at an important stage of breast development, and it is an important time in a woman’s life when her breast development is perfect or not. If a fibroadenoma is found in the breast at this stage of development, it should be treated surgically as soon as possible. The reasons for this are: (1) During the developmental stage, estrogen has an unbalanced effect on both breasts: the glandular ducts, fibrous tissues and fatty tissues in the breasts can grow in different degrees under the effect of estrogen. If the local breast tissue becomes more sensitive to estrogen, it will develop into fibroadenoma, at which time the tumor can grow rapidly under the state of high estrogen level, sometimes growing larger. Because the tumor occupies the breast, it affects the normal development of the breast and makes the breast shape smaller than the opposite side. In addition, because the tumor can absorb a large amount of estrogen during the rapid growth process, the breast tissue can also affect the development of the breast due to the decrease of estrogen, resulting in a large and small breast. (2) Malignancy: Due to the high estrogen level during the developmental stage of adolescence, there is often a possibility of malignancy based on fibroadenoma, and breast cancer in adolescent girls has also occurred repeatedly. For this reason, girls with fibroadenoma should be treated surgically sooner rather than later.