How to tell the difference between mammory gland and breast lump?

Only w/ microscope: Palpating the breast may show a lump. It is not possible to determine exactly what the lump is without a biopsy. To determine when a biopsy should be considered, docs consider patient age, prior history, whether the lump is changing or is associated with other signs like dimpling, family history and some other personal factors. A mammogram can increase or decrease concern as well.