Physical examination is an important method to diagnose breast diseases The breast is an organ located on the surface of the body, so it is easier to perform physical examination when lesions occur; however, the breast is an important endocrine organ of women, which can have different changes at different times of life and during the menstrual cycle, sometimes it may conceal the existence of malignant tumors, and sometimes it may mistake normal changes for tumors (Table 3-1). Therefore, a careful and proper breast physical examination can help detect breast tumors as well as identify benign and malignant changes in the breast. When there is a lump in the breast, a physical examination by an experienced breast specialist may have a higher diagnostic accuracy than ancillary examinations such as mammograms. Table 3-1, Conditions that cause confusion in breast diseases Lobular hyperplasia and early breast cancer Acute mastitis and inflammatory breast cancer Glandular hypertrophy during pregnancy and lactation and breast cancer during pregnancy and lactation Plasmacytoid mastitis and mid- to late-stage breast cancer Inflammatory erosions of the nipple and Paget’s disease of the breast Surgical scarring of the breast and recurrence of breast cancer Male breast hypertrophy and male breast cancer Sebaceous cysts and lipomas of the breast and breast Masses Fibroadenoma of the breast and early lobulated cystic sarcoma