Abstract: Objective:To explore the breast ultrasonographic and pathologic characteristics of breast phyllodes tumor(PTB),and the breast sentinel lymph node involvement of different types phyllodes tumor.Methods:The data of breast ultrasonography findings and sentinel lymph node biopsy in 45 cases with PTB diagnosed by pathology were retrospectively analyzed,which was compared with pathological results.Results:Among 45 cases(49 PTBs),benign tumor in 31 cases,borderline tumor in 12 cases and malignant tumor in 6 cases were identified.All mass were substantial low echo or mixed echo,the lobulated form and clear boundary was more common(P<0.05),and the internal echo was uneven.Color Doppler showed that the level Ⅱ-Ⅲ blood flow signal was found in 59.2%(29/49) mass.The clear boundary in benign lobulated tumor was more common(P<0.05),and the sentinel lymph node of which was not involved.The polycystic change in malignant tumor inner was found(P<0.01),and the sentinel lymph node of which was involved(P<0.01).Conclusions:The sonographic findings of PTB has certain characteristics,and the clear boundary of mass,cystic change of tumor inner complicated with axillary lymph node involvement are important basis in identifying benign and malignant tumor.