3 Rules to Correct Benign and Malignant Skin Lesion Excision Coding


By G.J. Verhovshek

Correct coding for excision of benign (11400-11471) or malignant (11600-11646) skin lesions is as easy as 1, 2, 3. Here’s what you need to know.

1. Measure First, Cut Second

When assigning CPT® codes 11400-11646, you must know precisely the size of the lesion(s) excised, as well as the width of the margins (the extra area immediately surrounding the lesion also removed). Per CPT® instructions, “Code selection is determined by measuring the greatest clinical diameter of the apparent lesion plus that [most narrow] margin required for complete excision."

The physician should measure the lesion and margins prior to excision. This is because the lesion will “shrink" as soon as the incision releases the tension on the skin.

2. Wait for the Path Report

CPT® codes for lesion excision (as well as ICD-9 diagnostic codes) require that you identify a lesion as either benign or malignant. For this reason, you should wait for the results of the pathology report before making a code selection. Only those lesions specifically identified as malignant may be assigned a code for malignancy.

There is one exception to the rule #2: If a surgeon performs a re-excision to obtain clear margins at a later operative session, you may report the same malignant diagnosis that you linked to the initial excision because the reason for the re-excision is malignancy.

3. Location Matters

Finally, you’ll need to know the anatomic location from which the lesion(s) is excised to determine proper coding. Multiple areas may be grouped together within a single set of codes, so pay careful attention to code descriptors.

To demonstrate our rules at work, let’s consider an example:

The surgeon excises a lesion from a patient’s right shoulder (location). Prior to excision, the lesion measures 1.5 centimeters at its widest; to ensure complete removal the surgeon allows a margin of at least 1.5 cm on all sides. Adding the largest diameter of the lesion (1.5 cm) to the narrowest margin (1.5 cm on each side, or 3.0 cm total) gives us an excised diameter of 4.5 cm (size before excision). Subsequent to excision, the pathology report identifies the lesion as malignant. The correct code is 11606 Excision, malignant lesion including margins, trunk, arms or legs; excised diameter over 4 cm.

When the physician excises multiple lesions, code each lesion separately, assigning a specific CPT® and ICD-9 code for every lesion treated. When coding multiple excisions classified together in the same anatomic location, append modifier 59 Distinct procedural service to the second and all subsequent codes describing lesion excision.

For example, the physician removes three lesions from the right arm. Pathology determines that two of these (with excised diameters of 1 cm and 1.5 cm) are benign; the third lesion (excised diameter 2.5 cm) returns malignant. You would code first excision of the malignant lesion because this is the “most extensive" procedure: 11603 Excision, malignant lesion including margins, trunk, arms or legs; excised diameter 2.1 to 3.0 cm (dx. 173.6 Other malignant neoplasm of skin, skin of upper limb, including shoulder). In addition, you would report the benign lesion excisions using 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 (dx. 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 (dx. 216.6).

Bonus Tip: Bundle Simple Repairs With Excision

Per CPT® guidelines, all lesion excision codes include simple wound closure. CPT® allows separate coding for intermediate (12031-12057) and complex (13100-13153) repairs; however, payers who follow National Correct Coding Initiative (NCCI) edits will bundle intermediate and complex repairs into excision of benign lesions of 0.5 cm or less (11400, 11420 and 11440).

G.J. Verhovshek, MA, CPC, is the managing editor and director of editorial development at AAPC (www.aapc.com), the nation’s largest education and credentialing association for medical coders.


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