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 to that measurement double the width of the narrowest margin.
Physicians should document the size of the lesion excision prior to removal. This is a matter of both clinical and coding accuracy. The lesion’s size will decrease as soon as the first incision releases some of the tension on the skin, and the sample will likely shrink further when placed in formaldehyde.
Be careful not to confuse the length of the incision with the width of the margins. Often, for instance, the physician will make an incision that is longer than the lesion to “flatten” the resulting scar, but this has no bearing on code selection. Base your measurements on the actual size of the lesion before the surgeon performs the excision and prior to sending it to pathology, not according to the size of the surgical wound left behind.
For example, a physician excises an irregularly shaped, malignant lesion from a patient’s right shoulder. Prior to excision, the lesion measures 1.5 centimeters 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 double the 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 cm.
Because CPT classifies lesions as either “benign” or “malignant,” you should always wait for the pathology report before selecting CPT or ICD-9 to describe the excised lesion(s). There is a single exception to this rule: If the surgeon performs a re-excision to obtain clear margins at a subsequent operative session, you may report automatically the same malignant diagnosis you linked to the initial excision. This is true even if the pathology report on the second excision returns benign, because the original reason for the re-excision was malignancy.
You should treat each 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.
For example, the physician removes three lesions — all from the left arm — with sizes 1 cm (benign), 1.5 cm (benign) and 2.5 cm (malignant). In this case, you should report: 11603 — Excision, malignant lesion including margins, trunk, arms or legs; excised diameter 2.1 to 3.0 cm with diagnosis 173.6 — Other malignant neoplasm of skin, skin of upper limb, including shoulder; 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 with 216.6 Benign neoplasm of skin; skin of upper limb, including shoulder, 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 with 216.6.
Note that all lesion excision codes include simple closure. CPT allows separate coding for intermediate (12031-12057) and complex (13100-13153) repairs, when required. Payors 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).
G. John Verhovshek, MA, CPC, is director of clinical coding communications for the American Academy of Professional Coders (AAPC), the nation’s largest education and credentialing association for medical coders. AAPC provides certified credentials to medical coders in physician offices, outpatient centers and medical insurance companies. The three certifications AAPC offers are CPC, CPC-H and CPC-P and represent the gold standard certification for medical coding.