For years, surgical excision has been the standard of care for women with proliferative lesions such as atypical hyperplasia or lobular carcinoma in situ identified on needle biopsy because of concern of co-existing occult cancer. However, emerging evidence has suggested a more personalized approach of identifying women for whom surgical excision may be appropriate. A number of variables have been shown to be associated with an increased risk of a pathologic upgrade; this affords the opportunity for selective surgical excision. All women with these proliferative lesions, whether diagnosed on needle biopsy or surgical excision, are at increased risk of future breast cancers and derive significant risk reduction with endocrine therapy. Unless contraindicated, all women with atypical hyperplasia and lobular carcinoma in situ should be started on preventive therapy.