The special attention the study of diagnosis and treatment of benign and precancerous lesions of breast JIANG Jun. Breast Disease Center, Southwest Hospital, the Third Military Medical University, Chongqing 400038, China Abstract Pathogenic mechanism leading to breast hyperplasia is still unclear, the standard of clinical diagnosis and treatment have not come to a consensus, the clinical characteristic and process of carcinogenesis from hyperplastic diseases of breast is unclear and there is short of effective clinical methods for monitoring the disease progression. In surgical management of breast fibroadenoma, how to obtain ideal cosmetic results needs to search for the principles of management and micro-invasive operation for micro-fibroadenoma. Difficulties still exist in prevention and treatment of breast fibroadenomas. The development and treatment of acute mastitis during lactation relating to polyacrylamide gel injection for breast augmentation have their specificities. And there is a lack of consensus on the treatment of plasma cell mastitis. Further and deeper study is still required for clinical detection and diagnosis of precancerous lesion and breast cancer in situ. The key of raising the therapeutic effect in treating benign breast lesions is to make efforts to explore methods solving these problems.