Why do they put pen mark on the area of breast that feels not right in one stop breast clinic.

Hi there I’m new here, i was just wondering why does the consultant in the one stop breast clinic put a pen mark a circle/ cross on the area of breast which is of concern??? 

They do the same when they do surgery. It pinpoints where the lump is, or lesion as they call it.  It seems a bit amateur, but there you go, they find it useful and it does stay in place for quite a long time if they use permanent pens. You don’t want them to do surgery on the wrong one. Good luck

Seagulls