How can someone have breast cancer in three different areas and what does that mean?

Multifocal: Breast cancer that occurs in more than one area is multifocal. Multiple sites of breast cancer may indicate increased risks of cancer in the breast cells and may indicate a need for mastectomy along with chemotherapy.

It can happen: Breast cancer typically starts in the breast but it can then spread to other parts of the body. When that happens it is called metastatic breast cancer or stage -4 breast cancer. In such cases multiple sites/organs are affected by breast cancer, typically it involves lungs, bones and liver but it can spread to any of the organs in the body.