Hello: Need some clarification for coding Proliferating Trichilemmal Cyst. We would always bill as 88304, but just today my Doctor came in and said he believes this is should be an 88305 not an 88304 because it is more tumor like than cyst like (and much more difficult to diagnose). I tried doing a little digging around and I can't seem to find a clear answer on this. Anyone have any insight/ or what do you code at? Thanks!!!