Multifocal breast cancer: refers to multiple lesions in the same quadrant, presumed to originate from the same tumor. Compared to unifocal breast cancer, multifocal breast cancer is more likely to develop lymph node metastasis, but does not affect overall survival. Multicentric breast cancer: refers to multiple lesions in different quadrants of the same breast. Two breast lesions with completely different pathological types (e.g. ductal and lobular carcinoma) and molecular typing (HER2-positive and triple-negative) are definitely a multicentric breast cancer.