The multiple tumors that your doctors found may have prompted him to suspect that this could be cancer metastatic to the breast rather than being a primary breast cancer. However, cancers metastatic to the breast (secondary cancers) are somewhat uncommon, and the more common cancer spreading to the breast is cancer coming from the other breast. This can still be primary cancer, it is just that the histology at the present may not be that clear. This could be a variant of breast cancer that is difficult to diagnose with routine pathology. Let's wait for the studies at Mayo Clinic and hopefully shed some light. But I think that this is still a primary breast cancer.
Regards and God bless.