Wuhan leaf plastic surgery expert: Hello! There is no breast tissue in the armpits. If there is, it is the accessory breast. Humans generally have only one pair of mammary glands, but a few people may have extra mammary glands. We refer to the extra mammary glands as accessory mammary glands. The location of the accessory breast is not necessarily certain. It appears along the position of the embryonic breast. Its most common locations are in the armpit and front of the chest. Accessory mammary glands differ from normal mammary glands in that, except for their location, they are often underdeveloped tissues and are generally smaller in size, ranging from the size of soybeans to as large as apricot kernels. Most accessory breasts only have breast parenchyma without nipples and areolas. The accessory breast has glandular tissue. Like normal breasts, it is affected by various sex hormones and may also experience swelling and pain before menstruation. The accessory breast can not only show cyclic changes under the influence of endocrine, but also can develop common diseases like normal breast tissue, such as adenomas, cysts, and breast hyperplasia. According to clinical experience, the rate of canceration of accessory breast after breast hyperplasia is higher than that of normal breast tissue. It is much higher. Therefore, we must pay attention to the treatment of accessory breast hyperplasia, which can be treated with oral administration of the series of medicinal patches for breast enhancement and external application of breast enhancement patches. Breast cancer can also occur in a small number of accessory breast glands, which is called accessory breast cancer. If the accessory breasts are all superior and do not require treatment, but if they are too large or suspected to be cancerous, surgical removal may be considered. Hope my answer can help you!