What exactly does it mean when they call you back for another mammogram?

Probably clear a sus: If they suspect something, they want further clarification by obtaining more pictures(different views of the breast).This is not uncommon.Most times it does not mean any bad news as the doubts are cleared and nothing worrysome is found.

Additional mammo: It means there is a possible abnormality present, but additional mammographic views are necessary to determine whether there is in fact an abnormality, or to better characterize an abnormality. Many times the additional mammo views show that there is nothing to worry about.