A small eye on the secondary breast is usually the breast duct of the secondary breast. In the process of breast development, only the breast in front of the chest is able to develop, and the breast tissue in other parts of the body will atrophy. If the breast tissue in other parts of the body does not atrophy, it is called paratesticular breast, which is usually located in the armpit, and manifests itself as the appearance of a swelling in the armpit. Sometimes the paratesticular breast will have a nipple, which is due to the nipple tissue not being degraded, and it manifests itself as the paratesticular breast with a small eye on it, and it is also an important clinical expression. After the appearance of paratesticular breast in the armpit, you need to go to a regular medical institution to be able to determine the severity of the condition, and then you can decide how to treat it, some patients can be regularly reviewed, and some patients need surgery.