Dr. Shilpy Dolas breaks down the common causes of breast lumps, when to worry, and when it's likely benign. Non-Cancerous (Benign) Causes Breast cysts: Smooth, round, fluid-filled sacs that can change in size with your monthly cycle. Fibroadenomas: Solid, rubbery, smooth tumors that move easily under the skin and are frequent in younger individuals. Fibrocystic changes: Ropelike, lumpy, or tender breast tissue tied to hormone shifts. Fat necrosis: Firm lumps formed after a physical injury or surgery to the breast. Breast abscesses or infections: Painful, red, swollen lumps filled with pus, often linked to breastfeeding. Intraductal papillomas: Small, wart-like benign growths inside the milk ducts that may cause discharge. Lipomas: Soft, harmless, movable fatty lumps Serious or Malignant Causes Breast cancer: Hard, painless lumps with irregular borders that do not move easily or change with your menstrual cycle. They may be accompanied by skin dimpling, nipple changes, or fluid leakage. How the lump feels (soft, hard, movable, or tender) Your age or if you notice changes with your cycle