It might be difficult in some cases to tell the difference on various xrays between myeloma and metastatic breast cancer; but it ought to be very easy to tell with other tests. A blood test might be all it takes.
Dear lisa mac: Breast cancer (metastatic to the bone) and multiple myeloma are two different diseases, diagnosed and treated entirely differently. Myeloma is a plasma cell problem that can cause significant bone damage. Breast cancer can also spread to the bone. This needs to be clarified.