Excision of Benign or Malignant Skin Lesion
To select an appropriate code for excision of a benign (11400-11471) or malignant (11600-11646) skin lesion, you must determine the lesion’s diameter at its widest point, and add double the width of the narrowest margin (the portion of healthy tissue around the lesion also excised).
In the interest of both clinical and coding accuracy, providers should document the size of the skin lesion excision prior to removal. The lesion will “shrink” as incisions release tension on the skin, and the sample may shrink when placed in formaldehyde.
Do not to confuse the length of the incision with the width of the margins. For example, a provider may make an incision that is longer than the lesion to “flatten” the resulting scar, but this doesn’t affect code selection. You should base your code selection on the actual size of the lesion before the provider performs the excision and prior to sending it to pathology, not according to the size of the surgical wound.
Example: A surgeon excises an irregularly shaped, malignant skin lesion from a patient’s right shoulder. Prior to excision, the lesion measures 1.5 cm at its widest. To ensure removal of all malignancy, the surgeon allows a margin of at least 1.5 cm on all sides. In this case, you would add the size of the lesion (1.5 cm) and the double width of the narrowest margin (1.5 cm x 2 = 3 cm) for a total of 4.5 cm. After considering location (shoulder), the correct code in this case is 11606 Excision, malignant lesion including margins, trunk, arms, or legs; excised diameter over 4.0 cm.
CPT classifies lesions as either “benign” or “malignant.” As such, you should always wait for the pathology report before selecting CPT or ICD-10 to describe the excised lesion(s).
There is an exception to the above rule: If the provider performs a re-excision to obtain clear margins at a subsequent operative session, you may report the malignant diagnosis linked to the initial excision. This holds true even if the pathology report on the second excision returns benign because the reason for the re-excision was malignancy.
Treat each skin lesion excision as a separate procedure, with an individual, dedicated diagnosis. In addition, you should append modifier 59 Distinct procedural service to the second and subsequent codes describing excisions at the same general location.
Example: The provider removes three lesions, all from the left arm, with sizes 1 cm (benign), 1.5 cm (benign), and 2.5 cm (malignant). You should report: 11603 Excision, malignant lesion including margins, trunk, arms or legs; excised diameter 2.1 to 3.0 cm, 11402-59 Excision, benign lesion including margins, except skin tag (unless listed elsewhere), trunk, arms or legs; excised diameter 1.1 to 2.0 cm, and; 11401-59 Excision, benign lesion including margins, except skin tag (unless listed elsewhere), trunk, arms or legs; excised diameter 0.6 to 1.0 cm.
Simple Closure Is Included
Note that all lesion excision codes include simple closure. CPT allows separate coding for intermediate (12031-12057) and complex (13100-13153) repairs, when required. Payers who follow national Correct Coding Initiative (CCI) edits, however, may bundle intermediate and complex repairs into excision of benign lesions of 0.5 cm or less (11400, 11420 and 11440).