Pain, a palpable mass, or nipple discharge often draws a patients attention to their breast. Common benign causes of breast mass vary in incidence with patient age. For patients under 25 years old, benign fibroadenoma is the most common cause of breast mass. For those between 35 and 50 years old, fibrocystic changes are very common (1 in 3 women) and may cause mass-like lumps in the breast. Mastitis and breast abscess may cause mass-like abnormalities in the breast, and are mostly found in lactating women. Phyllodes tumors commonly affect women in their 40s and 50s, and papillary adenoma of the nipple is also common in women in their 40s. Above the age of 50 years, the inci­ dence of cancer in a mass increases, and in those aged 60 years or more it is the most likely diagnosis. Table 2.1 lists the age-related risk rates for the general population.