Xiao Liu is a junior student in a university. One day before her menstruation, she suddenly felt a gradual swelling and pain in her armpits, and when she touched them with her hands, she felt an egg-sized lump on each side. The day before her period, she suddenly felt a gradual swelling and pain in her armpits. The more she thought about it, the more scared she was and hurried to the hospital accompanied by her boyfriend. The company’s main goal is to provide a comprehensive range of products and services to the public. So, what exactly is going on with the parametrium? Will it affect health? I. What is a parametrium? Parametrium, as the name implies, is an extra breast. Under normal circumstances, women only have one pair of breasts, but some women also have breasts and nipples in other parts of the body besides the breasts. Embryology tells us that parametrium is brought from the fetus. In the sixth week of embryonic life, the ectodermal cells thicken on both sides of the ventral surface of the trunk, forming ridges that correspond to the curved line from the armpit to the groin, and these two ridges are called the mammary line, with 6-8 pairs of mammary primordia. Since humans generally give birth to only one or two children at a time and do not need many mammary glands to nurse, only the first pair of mammary glands on the chest continue to develop and form nipple buds. By the third month of embryonic life, the mammary ducts are formed. The rest of the mammary primordia gradually degenerate and disappear. If the degeneration is incomplete, extra breasts are formed after birth, which is medically known as parametria or polymastia. After the birth of a fetus, the remaining parametrium can be hidden. After puberty, especially during pregnancy and breastfeeding, the hormone levels in the body will increase and the remaining breast primordia will grow and form lumps, and in some cases, lactation. Where do the parastomasum grow? The incidence of parastomal breast is 1% to 5%, and there is often a genetic tendency. The ratio of male to female is 1:3~5, i.e., it can occur in both men and women, but is more common in women. They are most commonly found in the anterior axillary line or underarm, but can also be found on the chest wall, abdominal wall, etc. Occasionally, they can be found in the ear, face, neck, upper arm, back, scapular area, groin, dorsal thigh, buttocks, vulva, etc., but are very rare. How many types of parastomastia are there? There are two types of parastomastia: fully developed and incompletely developed. The fully developed parametrial breast has both nipples and breast tissue, and may appear swollen and painful with the menstrual cycle and disappear after menstruation. During pregnancy, the breasts swell with development, and during breastfeeding, milk can be discharged from the parametrial nipple, which becomes soft after weaning and shrinks. Incompletely developed parametrium has only areola or nipple, or there may be only incompletely developed breast tissue, without nipple, areola and duct system. Therefore, it is often overlooked because there is no special sensation. How to diagnose parametrial breast? Through medical history and physical examination, the diagnosis of parametrial breast is not difficult. The fully developed parametrium is usually a bulge or lump with a diameter of 1-6 cm and a soft texture, with the nipple and areola visible in the center. The size may increase during menstruation or lactation, with painful swelling or milk secretion. The incompletely developed parametrium usually has no obvious discomfort. On physical examination, subcutaneous masses or nipples and areolas can be seen. They can sometimes be mistaken for axillary lipomas or enlarged lymph nodes in the armpit or for growths in the caudal part of the normal breast, but they can usually be distinguished by mammography. V. How are parametrial breasts treated? The treatment principle for parametrial breast is the same as normal breast, no treatment is needed if there is no disease, especially if the parametrial breast is asymptomatic and small in size. However, because the structure of the breast tissue of the parametrial breast is the same as that of the normal breast, the parametrial breast can also suffer from various diseases that can occur in the normal breast, such as hyperplasia, inflammation, and cancer. Therefore, it is necessary to seek medical attention when the following conditions occur (1) If there is frequent swelling and pain before menstruation; (2) If there is an abnormal lump or suspected tumor in the secondary breast; (3) If there is localized eczema or infection in the secondary breast; (4) If the secondary breast is large and affects the appearance. Special emphasis should be placed on whether surgery is needed for the parametrial breast and which type of surgery should be performed at a regular hospital breast clinic. Surgical treatment usually requires hospitalization. Routine frozen pathological examination should be performed during surgery to avoid misdiagnosis. The most effective way to prevent parametrial cancer is self-examination once a month and physical examination once a year. If the parametrial cancer is close to the normal breast, the ipsilateral breast should be removed. Patients with early stage parametrial cancer can have a better prognosis through surgery, chemotherapy, radiotherapy and endocrine therapy.