One day, a woman came to my clinic for treatment with a few months old baby in her arms. This lady told me that after giving birth to a baby, her right armpit always has a lump and pain repeatedly, and sometimes it is accompanied by a fever. She went to the clinic for examination, and the doctor said that she had acute lymphadenitis, so it would be fine to drip antibiotics intravenously. After each drip, the lump disappeared quickly, but it didn't take long for it to recur, and it was repeated several times. The attack was because the weather turned cold, and the tumor in the right armpit quickly grew up again, accompanied by a high fever. She had to go to a big hospital for emergency treatment. Results The doctor said that the tumor under her armpit was not acute lymphadenitis at all, but accessory mammary gland inflammation during lactation, and the doctor suggested that she had better have it removed surgically. She was puzzled. She has heard of accessory mammary glands before, but only knows that it has little impact on health and can be left untreated. Why did the doctor want her to have it surgically removed? She suspected that the doctor was exaggerating deliberately, so she came here to see me. After listening to her story, I gave her a physical examination and found that the lump in her right armpit was indeed inflammation of the accessory breast and had suppurated. In the symmetrical part of her left armpit, you can also see the nipple and feel the thickened fat mass. The doctor's advice is reasonable. It seems that people don't know enough about the occurrence, disadvantages and harm of accessory breast. Accessory breast is an atavistic phenomenon. Accessory mammary gland belongs to embryonic 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. Whether the auxiliary milk affects health depends on the situation. Some accessory mammary glands only have nipples and areola, and there is no glandular tissue, so there is no possibility of canceration, which has little effect on the body. Some accessory mammary glands have the same tissue structure as normal mammary glands and are also influenced by female hormones, and have the same physiological characteristics and pathological changes as normal mammary glands. For example, accessory mammary glands can be swollen and painful during menstrual cycle, pregnancy or lactation, and a small amount of milk can be secreted during lactation, especially when a few accessory mammary glands in the chest communicate with normal mammary glands, the secreted milk can be emptied to normal mammary glands. If the accessory breast is not connected with the normal breast or has no nipple, the milk secreted by it will accumulate because it cannot be emptied, which will cause swelling, inflammation and even suppuration. In addition, mastitis, lobular hyperplasia of breast, even benign tumor and breast cancer can occur in accessory breast, and its incidence rate is higher than that in normal breast. Moreover, the rate of clinical misdiagnosis caused by it is much higher. For example, paramilitis under the armpit is often misdiagnosed as lymphadenitis by doctors, lobular hyperplasia of accessory breast is misdiagnosed as lipoma, and even accessory breast cancer is diagnosed as common lymphadenitis. From this point of view, the disadvantages and harm of accessory breast disease far exceed that of normal breast. Do you need surgical resection? Since the harm of accessory breast is so great, is it necessary to remove it surgically? Not really, it depends on the specific situation. As mentioned above, some auxiliary breasts only have nipples and areola, and there is no glandular tissue. Such auxiliary breasts are unlikely to become cancerous. If it does not affect the appearance and physical activity, and there are no symptoms at ordinary times, you can not treat it. In addition, because the existence of accessory milk has no benefits to the body, and there are many disadvantages and great harm, for the sake of safety, surgical resection is still recommended. The common indications for surgery are: ① obvious symptoms such as swelling, pain and tenderness of accessory breast accompanying menstrual cycle, which affect daily life; (2) The accessory mammary gland is too large, which affects physical activity (if it grows under the armpit, it affects the adduction activity of the upper arm); (3) Accessory mammary glands have affected the beauty, which in turn affects patients' life and social interaction; ④ Inflammation has occurred and disappeared after conservative treatment, but the mass still exists; ⑤ If the accessory breast has become cancerous, it should be clearly excluded whether the normal breast has also become cancerous. If it has been affected, the corresponding cancerous breast should be completely removed at the same time as the accessory breast is removed. In addition, if the accessory breast only has breast tissue, without nipple and areola, and becomes a suspicious mass, it can't be differentiated from lipoma or enlarged lymph nodes for a while, you can ask the medical history in detail to see if it is related to menstrual cycle, pregnancy and lactation, and make a biopsy to make a definite diagnosis if necessary. Because the armpit is a place with dense lymph nodes, once the 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.