Part B Insider (Multispecialty) Coding Alert

Question: When our surgeon excises multiple lesions, I’ve heard that we should we add the sizes together and bill for one excision. Is that correct?

Answer: No, that is not correct, although it is a "common misconception," according to CPT® Assistant.

Do this: You should separately bill for each lesion using modifier 59 (Distinct procedural service) or perhaps multiple units of service, depending on payer instruction. The only exception is if the surgeon excises two lesions close together, using only one excision.

Source of confusion: Coders may be mixing up lesion excision rules with the rules for laceration repairs, which are different. With laceration repairs, you do add the lengths of tissue repaired and bill one code.

With lesion excision, you should calculate the size of the excision by measuring the size of the lesion plus the size of the margins necessary to ensure a clean margin.

Why? The instructions for benign lesion excision (11400-11446, Excision, benign lesion including margins …) and malignant lesion excision (11600-11646, Excision, malignant lesion including margins …) both state that you should "Report separately each … lesion excised."

Measure carefully: Although you won’t add the numbers together for your code choice, the surgeon does need to carefully measure and document the size of the lesion and the margins in order to select the proper code.

For both malignant and benign lesions, the size you report, and thus the code you select, is "determined by measuring the greatest clinical diameter of the apparent lesion plus the margin required for complete excision." You’ll need to add the lesion plus the margin x 2 (because the margin is all around the lesion, so it shows up on both sides as you measure across the largest diameter).