Parametrium is a common abnormally developed breast in women, it is often an underdeveloped tissue, mostly like a baby’s breast, or only a little skin pigmentation is seen, and there can be a small amount of skin increase after the center, similar to a small nipple; there are also cases with well developed nipple areola. Some have only mammary glands, some have only nipples, but there are also intact breast nipples, areolas, and glands) visible in the axilla or below the normal breast, and they are larger. Before menstruation, the parametrium is also swollen and painful, and it is obviously enlarged when expecting, and there are nipples that even secrete milk during the prolactation period. The incidence is 1% to 6%. It can occur in both men and women, more in women than in men (5U1), and is often hereditary. Parametrium can occur anywhere in the breast line between the upper and lower extremities, and the parametrium is mostly located in the lower part of the breast and around the axilla, and can be located above or below the normal breast.