Dermatology billing
A dermatology encounter can generate a biopsy, a destruction, an excision, a repair and a pathology service, and the correct codes for them depend on facts that are not all known when the patient leaves: the measured size, the count of lesions treated, and whether the pathology comes back benign or malignant. That gap between the visit and the finished claim is what makes the specialty's revenue cycle distinct.
- Lesion codes turn on anatomic site, measured size and lesion count, not on the diagnosis alone
- Benign and malignant excisions are separate code families, so pathology decides the code
- Mohs surgery is reported by stage and by tissue block, and bundles its own pathology
- Cosmetic removal is a non-covered benefit question, not a coding question
This is an educational guide to how billing works for dermatology — its workflow, coding, and payer considerations. It is general information, not a statement that US Medical Billing serves this specialty, and not billing, coding, or legal advice.
What makes dermatology billing distinct
Most specialties select a procedure code from what was done. Dermatology selects it from what was done plus how big it was, where on the body it was, how many there were, and -- for excisions -- what the tissue turned out to be. CMS treats the whole of this as one removal event: its National Correct Coding Initiative policy manual states that only one removal code may be reported for a lesion, that a single excision of skin containing several nevi is still one removal, and that if a removal is begun by one method and converted to another, only the completed procedure is reported. Coding a skin procedure is therefore an act of reconstruction from the operative note, not a lookup.
The same logic runs through what is bundled. Procurement of tissue from the same lesion by biopsy at the same encounter is included in the removal code, so a biopsy is separately reportable only when it was taken from a different lesion. Simple closure is included in the removal; intermediate and complex repairs may be reported separately -- except for excision of benign lesions at the smallest excised diameters, where CMS says the repair is included whatever its complexity. A practice that bills the repair every time and a practice that never bills it are both wrong, and the record is what decides which.
Coverage adds a second axis. Removing a lesion because it bleeds, is painful, obstructs a function or is suspicious is a covered medical service; removing the same lesion because the patient dislikes it is cosmetic and is not a covered benefit at all. Medicare contractors publish local coverage determinations that list the clinical findings supporting removal, and the national coverage determination on actinic keratosis takes the opposite approach -- covering destruction of these premalignant lesions without restrictions based on lesion or patient characteristics. Two lesions on the same arm can therefore follow entirely different coverage paths.
How dermatology billing flows
A dermatology revenue cycle has an extra loop in it: the claim waits for the pathology report. Each stage below carries a control that, if skipped, shows up later as a downcode, a bundled line or a denial.
Benefit check and the cosmetic conversation
Coverage and any plan-level exclusions are confirmed before the visit. Where a requested removal is likely to be cosmetic rather than medically necessary, the non-covered status is established with the patient in advance -- for Medicare beneficiaries, through an advance beneficiary notice -- so the balance is not a surprise after the fact.
Common operational challenges
The friction in dermatology billing sits where clinical documentation, specimen handling and coding meet -- and most of it is created in the room, not in the billing office.
Capturing size before, not after
The measurement that drives an excision code has to be taken while the lesion is still on the patient and must account for the margins. A note that records the specimen size instead of the excised diameter understates the procedure and cannot be corrected afterwards.
Counting lesions consistently
Destruction and paring procedures are billed by how many lesions were treated. When the note describes the encounter narratively rather than listing treated lesions by site, the units on the claim become an interpretation rather than a fact.
Running a pending-pathology queue
Excision claims wait for the pathology report to distinguish benign from malignant. Without a worklist that tracks which encounters are held and why, those claims either age quietly or go out coded on assumption.
Separating the medical from the cosmetic
A dermatology visit routinely mixes covered and non-covered work. Deciding which is which, documenting the findings that make a removal medically necessary, and settling patient responsibility before the procedure are recurring front-desk problems, not billing ones.
Documentation and coding considerations
Dermatology coding depends on four variables the clinical note has to state plainly: method, site, size or count, and -- for excisions -- the pathology result. The CPT code set is maintained by the American Medical Association; the notes below describe documentation considerations rather than reproduce any code descriptions.
Method decides the code family
Destruction, paring, shaving, biopsy and excision are distinct families, and only one removal code may be reported for a given lesion. Where a procedure begins as one method and is completed as another, only the completed procedure is reported.
Excised diameter, not specimen size
Excision codes are selected on the excised diameter -- the lesion plus the narrowest margins actually taken -- measured before excision. Simple closure is included; at the smallest benign excised diameters (11400, 11420, 11440) CMS states that simple, intermediate and complex repairs are all included and may not be reported separately.
Biopsy at the same encounter
Removal codes include obtaining tissue from the same lesion by biopsy at that encounter, so biopsy codes 11102-11107 are separately reportable only for a biopsy of a different lesion. CMS specifically names the biopsy-with-destruction pairs (11102, 11104, 11106 against 17000 and 17004) as edits that are often bypassed with a distinct-service modifier where the two procedures were not, in fact, on separate lesions.
Mohs micrographic surgery
Mohs (17311-17315) is reported by stage and by the number of tissue blocks within a stage, and its defining condition is that a single physician performs both the surgery and the pathologic examination. The Mohs codes include the biopsy, excision and pathology services for that specimen, so reporting those separately is incorrect coding; repairs, grafts and flaps remain separately reportable.
Denial and rejection risks
Dermatology denials cluster in three places: a coverage policy the record does not satisfy, an edit bypassed with a modifier the record does not support, and a service that was never a benefit in the first place.
Benign removal without the covered indication
Local coverage determinations on removal of benign skin lesions list the findings -- bleeding, pain, obstruction of a function, suspicion of malignancy and similar -- that make removal medically necessary. A note that records the removal but not the finding is denied as cosmetic or not medically necessary, whatever the clinical reality was.
Distinct-service modifiers on the same lesion
Modifier 59 and the X-modifiers state that two services were separate. Applied to a biopsy and a destruction performed on the same lesion at the same encounter, that statement is untrue, and CMS names this pattern in its own policy manual -- which makes it a recovery-audit target as well as a denial.
Modifier 25 that only reports the decision
The decision to perform a minor procedure is already paid inside the procedure. A same-day evaluation and management service is separately reportable only when significant work went beyond that decision, and CMS states plainly that a patient being new to the practice is not on its own a justification.
Pathology units that do not match the specimens
Surgical pathology is reported per specimen, not per lesion. Several lesions submitted in one container support one pathology code even if each is processed separately, so units billed from a lesion count rather than a specimen count will not reconcile.
Payer-process considerations
Dermatology is unusually exposed to written coverage policy, because so much of its volume is the removal of things that may or may not need removing.
Local coverage determinations set the bar
Medicare contractors publish local coverage determinations and companion billing-and-coding articles for lesion removal, and they differ by jurisdiction. The applicable policy for the practice's contractor is the operative document, not a general rule.
National coverage where it exists
For actinic keratosis, CMS resolved the question nationally: destruction of these lesions is covered without restrictions based on lesion or patient characteristics. Contractors still determine how many visits are reasonable to treat them, so frequency remains a local judgment.
Non-covered cosmetic services
Purely cosmetic removal is outside the benefit rather than denied on medical necessity. For Medicare beneficiaries that distinction drives whether an advance beneficiary notice is required before the service to make the patient responsible for the charge.
Global periods on minor procedures
Skin procedures carry short global periods, so a return visit inside the window is presumed related unless the record and the modifier say otherwise -- modifier 24 for unrelated care in a postoperative period, modifier 58 for a staged or planned procedure such as a biopsy followed by definitive surgery.
Revenue-cycle checkpoints
These are the points at which a dermatology claim is usually saved or lost. Most of them happen before the coder ever sees the chart.
- Confirm coverage and settle cosmetic versus medically necessary status before the procedure, with an advance beneficiary notice where one is required
- Record excised diameter -- lesion plus margins -- measured before excision, not the size of the specimen
- List every lesion treated by anatomic site so destruction and paring units are a count, not an estimate
- Label and submit specimens so that the pathology units billed match the number of specimens, not the number of lesions
- Hold excision coding until the pathology report distinguishes benign from malignant
- Check the applicable local coverage determination for the contractor before appealing a benign-removal denial
Related & connected
Services, tools, background reading and definitions that connect to the dermatology revenue-cycle steps above.
Related services
- Coding supportLesion code selection, excised-diameter documentation, modifier accuracy and NCCI-edit review for skin procedures.
- Denial managementWorking coverage-policy and bundling denials on lesion removal, and appealing with the findings the policy asks for.
- Patient billing & supportHandling the patient-responsibility side of cosmetic and other non-covered dermatology services.
Calculators & tools
- Modifier 25 and 59 documentation checklistCheck whether the record supports a same-day E/M or a distinct-service modifier before the claim goes out.
- ABN issuance checklistConfirm an advance beneficiary notice is valid before a likely non-covered removal.
- Denial rate calculatorSize how often claims are denied so coverage-policy and modifier issues can be prioritized.
From the Knowledge Base
- National and local coverage determinationsHow NCDs and LCDs work, and why a lesion-removal denial usually starts with a contractor's written policy.
- Medical necessity denialsWhy a medically appropriate procedure can still be denied against a coverage policy, and how to answer one.
- The Advance Beneficiary NoticeWhen an ABN is required before a service Medicare is unlikely to cover, and what makes one valid.
Glossary
- Modifier 25The significant, separately identifiable E/M service billed on the same day as a procedure.
- Modifier 59The distinct-procedural-service modifier used to separate services that an edit would otherwise bundle.
- Global periodThe window after a procedure in which related follow-up care is already paid for.
- Local coverage determinationA Medicare contractor's written policy on when a service is reasonable and necessary in its jurisdiction.
Frequently asked questions
Why is a lesion measured before it is excised rather than after?
Excision codes are selected on the excised diameter, which is the lesion plus the narrowest margins actually taken. Once the tissue is removed and placed in fixative it shrinks, so a measurement taken from the specimen understates what was excised and cannot be reconciled with the operative note. The measurement has to be recorded while the lesion is still on the patient.
Can a biopsy be billed with a removal performed at the same visit?
Only if the biopsy was taken from a different lesion. CMS states that removal codes already include obtaining tissue from the same lesion by biopsy at the same encounter, so billing both for one lesion is unbundling. Where the biopsy genuinely was of another lesion, a distinct-service modifier and documentation identifying both sites are what support the second line.
What makes Mohs surgery different from an excision?
Mohs micrographic surgery is reported by stage and by the number of tissue blocks examined within each stage, and it requires that one physician act as both surgeon and pathologist for the specimen. Because the codes already include the excision and the pathology for that specimen, those services are not reported separately -- although repairs, grafts and flaps still are.
Why was a removal denied as cosmetic when the patient asked for it to be removed?
Whether a removal is covered depends on documented clinical findings, not on the request. Medicare contractors publish local coverage determinations listing the findings -- bleeding, pain, obstruction of a function, suspicion of malignancy and similar -- that make removal reasonable and necessary. If the record does not state one of them, the service is treated as cosmetic and falls outside the benefit rather than being a coding error.
Sources
Last reviewed July 31, 2026.
- Centers for Medicare & Medicaid Services (CMS)National Correct Coding Initiative Policy Manual, Chapter III (Surgery: Integumentary System) -- lesion removal, repair, Mohs and pathology reporting rules
- Centers for Medicare & Medicaid Services (CMS)National Coverage Determination 250.4, Treatment of Actinic Keratosis
- Centers for Medicare & Medicaid Services (CMS)Medicare Coverage Database -- local coverage determinations and billing-and-coding articles on removal of benign and malignant skin lesions
- American Academy of Dermatology (AAD)Dermatology coding resources and practice guidance
Ready to improve your revenue cycle?
Tell us about your practice and we’ll tell you where we would start.