Modern female experts in Wuhan explained that accessory breasts are atavism. Accessory milk belongs to embryo residue. Just like a few people have long tails, vice breasts can also be regarded as an atavism. As we all know, humans evolved from mammals, and mammals generally have multiple breasts. In the process of human embryo development, there are many pairs of breasts at the beginning, which are distributed on the abdominal wall and are called mammary primordia. By the ninth week of the fetus, the rest of the breast primordia degenerated and disappeared, leaving only a pair of breasts to develop into normal breasts. If other breast primordia do not degenerate, multiple breasts or nipples will be formed. Accessory breasts often grow on the lower inner side or upper outer side of normal breasts, most commonly in armpits, occasionally in other parts of the body, such as abdomen and groin, and rarely in ears, face, neck, upper arms, vulva and buttocks. Accessory breasts can be symmetrical or unilateral, which is really varied.

Modern female experts in Wuhan explained that because axillary lymph nodes are densely populated, once accessory breast cancer grows here, it is easier to metastasize in the early stage. Therefore, all women's axillary swelling and pain with menstrual cycle, even if it is not a malignant tumor, should also consider surgical resection to prevent the occurrence of cancer. The lady mentioned at the beginning of the article, because her accessory breast grows under her armpit and is inflamed and swollen repeatedly, has affected her daily life and has potential cancer, so it is recommended to have it removed surgically.