Coding Uncertain Lesion Excisions With Certainty
What to do when the pathology doesn’t correlate to the service provided.
The rules for cutaneous (skin) excision coding are straightforward: When the pathology for a lesion is benign, code for excision of benign lesion, 11400-11446; and when the pathology for a lesion is malignant, code for excision of malignant lesion, 11600-11646. But in the real world, coding isn’t always that clear cut. Such is often the case when coding for excisions of neoplasms of uncertain nature.
Unspecified vs. Uncertain: There’s a Difference
Unlike an “unspecified neoplasm” diagnosis, which means the tissue has not been evaluated by a pathologist; therefore, it is unknown to the surgeon if the tissue is malignant or benign, a neoplasm of “uncertain nature” has been thoroughly evaluated by a pathologist; however, the pathologist was unable to classify the tissue’s cells as either malignant or benign. In other words, the morphology of the cells is uncertain. Only a pathologist can assign uncertain nature to a sample.
Because there is a chance that the tissue/cells could behave like malignant tissue/cells, the surgeon will treat lesions of uncertain nature as if they are malignant lesions by removing them with larger margins to make sure all the questionable tissue is removed.
A Case for Re-excision
So, what happens if the pathology report shows the sample from the re-excision performed at a separate encounter does not contain any malignant tissue? Per the May 2012 CPT® Assistant, even if the subsequent pathology comes back with a different diagnosis, the re-excision should be linked to the original (malignant) diagnosis. Let’s look at two examples demonstrating how proper procedure and diagnosis coding affects payment for re-excision on a patient who had been diagnosed with melanoma.
The surgeon re-excised a 2.2 cm area on the neck with 2 cm margins, making the diameter of the excision 6.2 cm. The sample was sent to pathology and found to be benign. The diagnosis code is C43.4 Malignant melanoma of scalp and neck.
Strict reading of the rules would have you code the procedure as an excision of a benign lesion since the pathology determined the sample to be benign — 11426 Excision, benign lesion including margins, except skin tag (unless listed elsewhere), scalp, neck, hands, feet, genitalia; excised diameter over 4.0 cm. This code has 8.00 facility relative value units (RVUs) with 4.09 work RVUs allocated to the surgeon.
For this encounter, however, the intent of the surgeon was to make sure the patient’s malignant lesion was fully excised, as indicated by the large margins and deep excision. While there is a benign tissue finding, the surgeon’s documented intent and approach was that for a malignant lesion excision, making the proper procedure code 11626 Excision, malignant lesion including margins, scalp, neck, hands, feet, genitalia; excised diameter over 4.0 cm. This service has 8.59 RVUs (4.61 work RVUs). Append modifier 58 if the same surgeon performed the re-excision during the postoperative period for the excision, per CPT® 2022 guidelines.
Note: These RVUs are all based on facility services, given the size of the lesions.
The surgeon excised a melanoma on the occipital scalp and a mass on the neck. The operative note stated that the neck mass was suspected to be a metastasis from the melanoma and, as a result, wider margins were excised, removing the lesion and the capsule in total. The pathology report indicated that the neck mass was a benign follicular cyst. Because of the excellent clinical documentation by the surgeon, the excision of the 3.5 cm diameter lesion and margins on the neck should be coded as an excision of malignant lesion, 11624 Excision, malignant lesion including margins, scalp, neck, hands, feet, genitalia; excised diameter 3.1 to 4.0 cm. This code has 6.95 RVUs, compared to 5.21 RVUs for 11424 Excision, benign lesion including margins, except skin tag (unless listed elsewhere), scalp, neck, hands, feet, genitalia; excised diameter 3.1 to 4.0 cm.
This coding is substantiated in CPT® Assistant (May 1996):
When the morphology of a lesion is ambiguous, choosing the correct CPT procedure code relates to the manner in which the lesion was approached rather than the final pathologic diagnosis, since the CPT code should reflect the knowledge, skill, time, and effort that the physician invested in the excision of the lesion. Therefore, an ambiguous but low suspicion lesion might be excised with minimal surrounding grossly normal skin/soft tissue margins, as for a benign lesion (codes 11400-11446), whereas an ambiguous but moderate-to-high suspicion lesion would be excised with moderate to wide surrounding grossly normal skin/soft tissue margins, as for a malignant lesion (codes 11600-11646). Thus, the CPT code that best describes the procedure as performed should be chosen.
Third-Party Payer Processing of Claim
There is a good chance that a third-party payer may deny a claim for excision of a malignant lesion with a diagnosis indicating that the lesion is benign or a cyst. If that occurs, the practice has two options:
1. Appeal the denial with a copy of the operative note which shows the surgeon assumed the lesion was malignant and treated the excision as such. Hopefully, your surgeon gives you a well written operative note, which demonstrates the medical necessity for excising a malignant lesion. Best practice would be to include the CPT® Assistant guidance provide above.
2. Submit the corrected claim for the excision of benign lesion with modifier 22 Increased procedural services. Include in box 19 that the lesion was assumed to be malignant, increasing the service by X percent.
You can also do this initially, instead of coding the service as a malignant lesion excision. The operative note should show the value of the service representing 15-35 percent more than the excision of a benign lesion, and the extra work involved because the surgeon assumed the lesion was malignant. This is typically quicker than appealing.
Get It in Writing
The difference in RVUs between benign and malignant lesion excisions is not huge; it’s more a matter of making sure the code most accurately represents the work the surgeon performed and documented. A Findings or Indications paragraph at the beginning of the operative note often provides a lot of quality information for the coder and anyone else evaluating the coding, such as the payer.
If the documentation does not clearly explain the indication(s) for the procedure (i.e., medical necessity), it is good protocol to query the surgeon to see if they would like to amend the operative note with the findings/indications that will help explain and support their work. We should strive to code what best represents the work performed by the surgeon.
CPT® 2022 Professional Edition, page 103.
CPT® Assistant, May 1996.
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