Diseases of the breast include benign and malignant diseases. Malignant diseases are mainly sarcomas of the breast and breast cancer, which occur more frequently in middle-aged and elderly patients. Patients with malignant breast tumors may present with painless breast lumps and bloody nipple discharge, which can be initially diagnosed by ultrasound or mammography. Malignant tumors are prone to axillary lymph node metastasis, early diagnosis should be timely choice of surgical treatment. Benign diseases include cystic hyperplasia of the breast, also known as mammary gland adenopathy, which occurs more often in middle-aged patients and is characterized by regular pain and lumps in the breast. Fibroadenomas of the breast and lipomas of the breast are also common. If the lesion grows in size, or if there is pain and discomfort, the most effective treatment is surgery, after which a pathologic examination is also required.