Abstract: Objective To investigate the clinical and pathological characteristics of multifocal and multicentric breast cancer.Methods We collected data of 56 cases of multifocal and multicentric breast cancer and 150 cases of unifocal breast cancer（control group）to analyze the clinicopathological features of multifocal and multicentric breast cancer.Results In both the multifocal and multicentric breast cancer and the unifocal breast cancer group，we found the histological type which was invasive lobular carcinoma accounted for 8.9% and 2.0%，respectively.The lymph node metastasis rate was 69.6% and 51.3%，respectively.The lymphatic vessel invasion rate was 35.7% and 13.3%，respectively.The mastectomy and breast-conserving surgery accounted for 92.9%，77.3% and 7.1%，22.7%，respectively.The differences were statistically significant（all P＜0.05）.The detection rate of ultrasonography in multifocal and multicentric breast cancer was 73.2%，and that was 51.8% of mammography.There was a significant difference between the two imaging methods（P＜0.05）.The sensitivity of the two imaging examinations combined to detect this type of patient was 82.1%.Conclusion Compared to unifocal breast cancer，our findings suggest that the risk of axillary lymph node metastasis and lymphatic vascular invasion in multifocal and multicentric breast cancer was higher，and that had a high proportion of invasive lobular carcinoma.Preoperative ultrasonography combined with mammography can increase the accuracy of diagnosis of multifocal and multicentric breast cancer.Multifocal breast cancer can be treated with breast conserving surgery on the premise of negative margin.

Key words: breast cancer, multifocal, multicentric, clinical, pathology