In a normal woman, there are breast glands, or nuclei, in the breast that feel a little hard when touched. The nucleus usually begins to appear during puberty and grows in size as a woman ages. This is a normal physiological phenomenon and usually does not require treatment. However, if a woman has hard lumps in her breasts as an adult, they may not always be nuclei, but may be symptoms of breast enlargement, breast fibroids and other diseases, and need to be examined at a hospital to clarify the cause and treat the symptoms. This is a sign that the breasts are starting to secrete milk. It is necessary to unblock the milk ducts in time to avoid acute mastitis caused by the accumulation of milk.