A hard lump on one side of the chest, that is, a hard lump in the breast gland, is seen for a variety of reasons: first, benign diseases, including fibroadenoma of the breast is also the most common. This disease occurs more often in young people, and the surface of the lesion is smooth, well-defined, well-moving and elastic, and surgery should be chosen for fibroadenoma of the breast. Secondly, malignant tumors of the breast, breast cancer is more common. The main manifestation is a painless lump in the breast, and some patients may even show a bloody overflow from the nipple. As the disease develops and evolves, it may also manifest as invasion of the suspensory ligament of the breast, dimple sign, and localized cellulite-like changes. For early diagnosis of breast malignancy, surgery should be actively chosen, and the occurrence of breast malignancy is also regulated by changes in hormone levels in the body.