Question: Kansas Subscriber Answer: In the example you give, the surgeon reported only the lesion size, not the margin. If that's all the information you have, you'll have to report the service based solely on the largest lesion diameter -- 2.5 cm, which reports to 11403 (Excision, benign lesion including margins, except skin tag [unless listed elsewhere], trunk arms or legs; excised diameter 2.1 to 3.0 cm). If your surgeon had documented the margins -- 0.5 cm at the narrowest, for instance -- you could calculate the size as 3.5 cm. That would code to 11404 (... excised diameter 3.1 to 4.0). If you're not adding in the margins for lesion excisions you're leaving money on the table.