Dermatology Billing: Biopsy, Mohs, Destruction, Pathology & Modifier Rules 2026

Dermatology claims can become difficult to bill when a single encounter involves multiple lesions, biopsies, destruction, Mohs surgery, pathology, and an office E/M service. The challenge is not simply selecting a CPT code. Practices must also determine whether services are bundled, whether a modifier is supported, and whether the documentation clearly establishes what was performed.

Here’s what dermatology practices should review before submitting these claims.

What Changed for Dermatology Coding in 2026?

One notable dermatology-related CPT revision is CPT 10040. Effective January 1, 2026, the CPT Editorial Panel accepted a revision changing the descriptor from “acne surgery” to “extraction,” covering procedures such as marsupialization and opening or removal of multiple milia, comedones, cysts, and pustules.

In 2026, dermatology practices also need to account for CPT updates and continuing NCCI requirements. CMS updates its Medicare NCCI Policy Manual annually and its procedure-to-procedure edits throughout the year.

This is a small wording change, but practices should update EHR charge descriptions, superbills, coding references, and internal cheat sheets so staff are working from the current 2026 terminology.

The larger billing issue remains correct code selection and compliance with NCCI edits.

1. Get Skin Biopsy Coding Right

Skin biopsies are primarily reported according to the technique performed, rather than simply the anatomical location.

Common biopsy codes include:

• 11102 – tangential biopsy, first lesion
• 11103 – each additional tangential biopsy
• 11104 – punch biopsy, first lesion
• 11105 – each additional punch biopsy
• 11106 – incisional biopsy, first lesion
• 11107 – each additional incisional biopsy

The documentation should identify the biopsy technique, lesion location, and clinical reason for obtaining the specimen.

The same-lesion rule matters

One of the most important 2026 NCCI considerations is the relationship between biopsy and lesion removal. Medicare NCCI states that lesion-removal services include procurement of tissue from the same lesion by biopsy during the same encounter. Therefore, biopsy codes should not simply be added to an excision or other lesion-removal service for the same lesion.

A biopsy performed on a different lesion may be separately reportable when supported by the applicable coding rules and documentation.

The practical lesson is simple: document each lesion separately.

For multiple lesions, identify the site, technique, diagnosis, and procedure performed for each lesion so the coder can establish which services are independently reportable.

2. Biopsy + Destruction: Don’t Use Modifier 59 Automatically

Another frequent dermatology billing problem occurs when a biopsy and destruction are reported on the same claim.

CMS specifically addresses NCCI edits involving biopsy codes 11102, 11104, and 11106 and destruction codes 17000 and 17004. Modifier 59, XE, or XS should not be used merely to bypass the edit. CMS states that these modifiers are appropriate in the relevant circumstances when the procedures are performed on separate lesions or at separate patient encounters.

That means a modifier should explain a genuine clinical distinction—not rescue an incorrectly bundled claim.

Before submitting the claim, ask:

Were the procedures performed on the same lesion or different lesions?

That question can determine whether the services are separately reportable.

3. Mohs Billing Requires Stage-and-Block Accuracy

Mohs micrographic surgery creates a different coding challenge because the procedure combines surgical removal with microscopic examination of the tissue.

The Mohs code family includes 17311–17315. CMS explains that these codes are reserved for the surgeon who removes the lesion, prepares the tissue, and interprets the slides. The Mohs service includes the associated pathologic examination performed by the Mohs surgeon.

The billing workflow therefore needs to distinguish:

• first-stage reporting,
• additional stages,
• tissue blocks,
• anatomical site,
• and separately performed services.

Don’t double-bill Mohs pathology

A common error is reporting surgical pathology codes for the same tissue already examined during Mohs.

CMS states that reporting both Mohs codes and surgical pathology codes for tissue used for Mohs margin evaluation is inappropriate.

However, CMS also recognizes situations in which a separate specimen is submitted to another physician for formal pathology. That specimen may be separately reportable when the clinical documentation supports the service.

The key distinction is not simply “in-house versus outside lab.” It is what tissue was examined, who performed the service, and whether that service is already included in Mohs.

4. Count Lesion Destruction Correctly

Destruction coding depends on the type and number of lesions treated.

For premalignant lesions such as actinic keratoses, the relevant code family includes:

• 17000 – first lesion
• 17003 – additional lesions, 2 through 14
• 17004 – 15 or more lesions

For benign lesions, the reporting structure is different:

• 17110 – destruction of benign lesions, up to 14
• 17111 – destruction of benign lesions, 15 or more

CMS guidance distinguishes these reporting rules and emphasizes that practices should select the code based on the lesion being treated and the applicable coverage requirements.

The procedure note should support the reported count. Instead of writing “multiple lesions treated,” document the number and relevant anatomical locations.

5. Modifier 25: Separate E/M From Procedure Work

Dermatology practices frequently evaluate a patient and perform a procedure during the same encounter. That does not automatically mean an E/M service can be reported separately.

Under 2026 NCCI guidance, modifier 25 may be appropriate when the E/M service is significant and separately identifiable from the procedure-related work. Importantly, the E/M and procedure do not have to have different diagnoses.

For example, simply examining a lesion and deciding to biopsy it generally represents work associated with the procedure. But a separately evaluated and managed problem may support an E/M service when the documentation establishes the additional work.

The note should make the separate E/M work identifiable rather than relying on modifier 25 alone.

6. Build Documentation Around the Lesion

A strong dermatology claim starts before coding.

For biopsy, destruction, or excision encounters, documentation should clearly identify:

• lesion location;
• procedure and technique;
• number of lesions;
• clinical diagnosis or reason for treatment;
• relevant measurements when required;
• specimen handling when applicable;
• pathology involvement;
• and separately identifiable E/M work when reported.

This creates a direct connection between the clinical note, diagnosis code, CPT code, modifier, and claim.

7. Audit NCCI Edits Before They Become Denials

NCCI is not a static list that practices can review once and forget. CMS updates the Medicare NCCI Policy Manual annually and publishes procedure-to-procedure edits on a quarterly basis.

For 2026, dermatology billing teams should periodically review:

CPT selection → NCCI edit → modifier requirement → documentation → payer policy

This is particularly important for claims containing multiple procedures.

A Practical Dermatology Billing Checklist

Before submission, ask:

1. Does the CPT code accurately describe the technique performed?
2. Are multiple lesions clearly identified?
3. Are biopsy and removal services being reported on the same lesion?
4. Does an NCCI edit apply?
5. Is modifier 25 supported by a separately identifiable E/M service?
6. Is modifier 59/XE/XS genuinely justified?
7. Is Mohs pathology already included?
8. Does the diagnosis support the procedure?
9. Does the claim match the operative or procedure note?
10. Has the payer’s current policy been checked?

Final Takeaway

Dermatology billing in 2026 is less about adding more codes and more about reporting the right service for the right lesion with documentation that supports the claim.

The most important areas to monitor are the 2026 CPT 10040 revision, biopsy and destruction NCCI edits, Mohs stage-and-block reporting, pathology bundling, lesion-count rules, and modifier 25 requirements. CMS guidance should be the starting point for Medicare claims, while commercial payer policies should be verified separately.

For dermatology practices, a proactive coding and billing review can identify overbundling and undercollection, unsupported modifiers, documentation gaps, and recurring denial patterns before they affect reimbursement.

Schedule an appointment with CloudRCM Solutions for a personalized billing and coding review.