The common causes of hard lumps felt on the breast are: 1, breast hyperplasia, manifested as multiple nodules of different sizes in both breasts with unclear boundaries, pain during menstruation or emotional changes, and pain can be relieved after menstruation, ultrasound suggests that the mammary glands are not homogeneous and have not yet developed a realistic nodule. 2, fibroadenoma of the breast, mostly a single nodule, with clear boundaries, smooth surface, good mobility, and a tough texture, can have pain when pressed. 3, intraductal papilloma of the breast, the lump appears near the areola, with a soft texture. There may be pain when pressed.3. Intraductal papilloma of the breast, the site of the lump is close to the areola, the texture is soft, and yellowish or bloody nipple discharge can be seen when squeezed.4. Dilatation of the breast ducts, also known as plasma cell mastitis, the lump is often with unclear margins, the surface is not smooth, and is often located in the depth of the areola.5. Breast cancer, the lump has a hard texture, unclear borders, and poor mobility, which may cause skin edema or partial The lump is hard, with unclear border and poor mobility, which may cause skin edema or localized depression.