Hi Im a new coder and a bit perplexed about all the lesion codes. The physician coded a 21930 for removal lesion that is 8-9 mm in size with changing colors. Is this the correct code to use for a mole that is changing colors? The insurance denied it saying it is a missing, invalid, or incomplete procedure code. It was billed with a 36415 and a 25 modifier. I would appreciate any information or web sites that teaches how to code things like this.