Math question answered
I'm a little confused by your question, MsAnna
The math is easy ... to find sq cm you multiply length x width.
The harder part is determining if you really need square cm or you just need length or diameter. You mention lesions .... if you are excising a lesion you measure across the widest diameter, plus smalled margin necessary for removal (physician should measure BEFORE surgery, and document this measurement in the operative/procedure note). If you are doing a tissue rearrangement, you will need the sq cm measurement of the flap and primary defect, added together; CPT tells us not to code the lesion removal separately in cases where the wound is closed via a flap.
All this information can be found by reading the guidelines in your CPT manual carefullly. Study the illustrations as well, because they provide some clarification.
Hope that helps.
F Tessa Barteles, CPC, CEMC