A hard lump is found in the breast and can slide up and down and from side to side. First of all, it is considered to be a case of breast fibroadenoma. Fibroadenoma of the breast is a benign tumor with clear, smooth, round or round-like borders that can slide when touched. Secondly, swollen lymph nodes in the breast can also appear as sliding lumps, which are caused by lymph node inflammation, lymphoma or malignant tumor metastasis, etc. The diagnosis is made by taking biopsies for pathological examination. Again, it is necessary to exclude lumps in the breast caused by lipomas, breast cysts, and breast hyperplasia. If you find a sliding lump in the breast, you need to go to the hospital for a detailed examination of the specific cause and timely treatment.