The Complete Guide to CPT Codes 11400–11646

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The Excision Billing Errors That Cost Dermatology Practices Revenue on Every Surgical Encounter

Excision billing is where dermatology revenue either gets fully captured or quietly disappears. The 11400–11646 code family, covering benign and malignant lesion excisions across all anatomical locations, is the highest per-procedure revenue opportunity in a dermatology practice. It is also one of the most frequently miscoded, underdocumented, and consistently underpaid code families in the specialty.

The reason isn't complexity for its own sake. It's three specific decision points that must all be correct simultaneously: lesion type (benign vs. malignant), total excised diameter including margins, and anatomical location. Miss any one of these and the wrong code gets selected typically a lower-value one and the practice absorbs a revenue loss it will never recover.

A single miscoded excision might cost $75–$150. Multiply that across 10 excisions per week for 50 weeks and the annual revenue leakage from excision coding errors alone reaches $37,500–$75,000 from procedures already performed. This guide gives your team the complete framework to stop that leak.

💡  Did You Know?

The #1 cause of excision undercoding in dermatology is failing to include the surgical margin in the excised diameter measurement. A 0.8 cm lesion with 0.2 cm margins on each side has a total excised diameter of 1.2 cm qualifying for a higher code tier than the lesion measurement alone suggests.

Malignant excision codes reimburse 40–60% more than benign codes at the same size and location. Coding a path-confirmed malignancy at benign rates is one of the most consistent and most significant revenue losses in dermatology surgical billing.

Body location is a co-equal determinant of code selection. The same 1.5 cm benign excision codes to 11402 on the trunk, 11422 on the scalp, and 11442 on the face — each at a meaningfully different reimbursement level. Using the wrong location family costs real money on every misclassified claim.

What Are CPT Codes 11400–11646 — And How Is This Code Family Structured?

The 11400–11646 family covers the surgical excision of skin lesions both benign and malignant — performed by full-thickness removal including the lesion and a surrounding margin of normal-appearing skin. The codes are organized across three intersecting dimensions that must all be correctly identified for accurate billing:

Dimension 1: Lesion Type — Benign vs. Malignant

Benign excisions (11400–11446): Lipomas, cysts, nevi, dermatofibromas, and lesions with no evidence of malignancy. Code selection based on clinical diagnosis and, where applicable, pathology confirmation.

Malignant excisions (11600–11646): Basal cell carcinoma, squamous cell carcinoma, melanoma, and other malignant neoplasms. These codes require pathology-confirmed malignancy and reimburse 40–60% more than benign codes at the same size and location.

Dimension 2: Total Excised Diameter — Lesion Plus Surgical Margins

This is the measurement that drives code selection within each location group and it must include the lesion plus the surgical margins on all sides. The total excised diameter is not the lesion size alone. It is the full diameter of the tissue removed.

The formula: Lesion diameter + margin side A + margin side B = Total excised diameter. A 1.0 cm lesion excised with 0.3 cm margins on each side has a total excised diameter of 1.6 cm — qualifying for the 1.1–2.0 cm code tier, not the 0.6–1.0 cm tier.

Dimension 3: Anatomical Location — Three Code Groups

Group 1 — Trunk, arms, and legs (11400–11406, 11600–11606): Lowest reimbursement tier.

Group 2 — Scalp, neck, hands, feet, and genitalia (11420–11426, 11620–11626): Mid-tier reimbursement higher surgical complexity considerations.

Group 3 — Face, ears, eyelids, nose, lips, and mucous membranes (11440–11446, 11640–11646): Highest reimbursement tier facial locations command premium values due to reconstructive complexity.

📊 CPT 11400–11646: Complete Code Reference — All 36 Codes with 2026 Reimbursement

Here is the complete 2026 reference guide for every code in the excision family benign codes in blue, malignant codes in orange organized by location group with size ranges and estimated reimbursement:

CPT Code	Lesion Type	Anatomical Location	Excised Diameter (Lesion + Margins)	Medicare Reimbursement	Commercial Average
11400	Benign	Trunk / Arms / Legs	≤ 0.5 cm	$130–$195	$175–$270
11401	Benign	Trunk / Arms / Legs	0.6–1.0 cm	$165–$240	$220–$320
11402	Benign	Trunk / Arms / Legs	1.1–2.0 cm	$205–$295	$270–$390
11403	Benign	Trunk / Arms / Legs	2.1–3.0 cm	$255–$360	$340–$480
11404	Benign	Trunk / Arms / Legs	3.1–4.0 cm	$310–$440	$415–$580
11406	Benign	Trunk / Arms / Legs	Over 4.0 cm	$390–$550	$520–$740
11420	Benign	Scalp / Neck / Hands / Feet / Genitalia	≤ 0.5 cm	$155–$225	$205–$300
11421	Benign	Scalp / Neck / Hands / Feet / Genitalia	0.6–1.0 cm	$195–$275	$260–$365
11422	Benign	Scalp / Neck / Hands / Feet / Genitalia	1.1–2.0 cm	$240–$340	$320–$455
11423	Benign	Scalp / Neck / Hands / Feet / Genitalia	2.1–3.0 cm	$295–$415	$390–$555
11424	Benign	Scalp / Neck / Hands / Feet / Genitalia	3.1–4.0 cm	$355–$500	$475–$670
11426	Benign	Scalp / Neck / Hands / Feet / Genitalia	Over 4.0 cm	$445–$630	$595–$840
11440	Benign	Face / Ears / Eyelids / Nose / Lips	≤ 0.5 cm	$185–$270	$245–$360
11441	Benign	Face / Ears / Eyelids / Nose / Lips	0.6–1.0 cm	$230–$330	$305–$440
11442	Benign	Face / Ears / Eyelids / Nose / Lips	1.1–2.0 cm	$285–$405	$380–$540
11443	Benign	Face / Ears / Eyelids / Nose / Lips	2.1–3.0 cm	$345–$490	$460–$655
11444	Benign	Face / Ears / Eyelids / Nose / Lips	3.1–4.0 cm	$415–$590	$555–$790
11446	Benign	Face / Ears / Eyelids / Nose / Lips	Over 4.0 cm	$520–$740	$695–$985
11600	Malignant	Trunk / Arms / Legs	≤ 0.5 cm	$205–$295	$275–$395
11601	Malignant	Trunk / Arms / Legs	0.6–1.0 cm	$255–$365	$340–$490
11602	Malignant	Trunk / Arms / Legs	1.1–2.0 cm	$310–$445	$415–$595
11603	Malignant	Trunk / Arms / Legs	2.1–3.0 cm	$375–$535	$500–$715
11604	Malignant	Trunk / Arms / Legs	3.1–4.0 cm	$450–$640	$600–$855
11606	Malignant	Trunk / Arms / Legs	Over 4.0 cm	$560–$800	$750–$1,070
11620	Malignant	Scalp / Neck / Hands / Feet / Genitalia	≤ 0.5 cm	$240–$345	$320–$460
11621	Malignant	Scalp / Neck / Hands / Feet / Genitalia	0.6–1.0 cm	$295–$420	$395–$565
11622	Malignant	Scalp / Neck / Hands / Feet / Genitalia	1.1–2.0 cm	$360–$510	$480–$685
11623	Malignant	Scalp / Neck / Hands / Feet / Genitalia	2.1–3.0 cm	$430–$610	$575–$820
11624	Malignant	Scalp / Neck / Hands / Feet / Genitalia	3.1–4.0 cm	$510–$725	$685–$975
11626	Malignant	Scalp / Neck / Hands / Feet / Genitalia	Over 4.0 cm	$635–$905	$850–$1,210
11640	Malignant	Face / Ears / Eyelids / Nose / Lips	≤ 0.5 cm	$275–$395	$370–$525
11641	Malignant	Face / Ears / Eyelids / Nose / Lips	0.6–1.0 cm	$335–$480	$450–$640
11642	Malignant	Face / Ears / Eyelids / Nose / Lips	1.1–2.0 cm	$405–$580	$540–$770
11643	Malignant	Face / Ears / Eyelids / Nose / Lips	2.1–3.0 cm	$480–$685	$645–$920
11644	Malignant	Face / Ears / Eyelids / Nose / Lips	3.1–4.0 cm	$565–$810	$760–$1,080
11646	Malignant	Face / Ears / Eyelids / Nose / Lips	Over 4.0 cm	$700–$1,000	$940–$1,335

⚠️  2026 Compliance Alert — Measurement Accuracy Is Actively Audited

CMS and commercial payers cross-reference operative note measurements against pathology specimen sizes. If your operative note claims a 2.0 cm excision but the pathology specimen is 0.8 cm, the payer expects margin documentation that accounts for the difference. Without clear margin documentation in the operative note, the code is indefensible in audit.

RAC auditors specifically target excision claims where code selection appears inconsistent with submitted diagnosis codes. A 11646 (malignant face, >4.0 cm) claim submitted with a benign ICD-10 diagnosis triggers automatic review.

How to Select the Correct Excision Code — Step-by-Step

Accurate code selection for the 11400–11646 family requires four sequential decisions, each of which directly determines which code is appropriate. Miss or rush any step and the wrong code gets selected.

Step 1: Confirm Lesion Type — Benign or Malignant

Before selecting any code, confirm whether the lesion is benign or malignant. For malignant codes, pathology confirmation is required — either from a prior biopsy result referenced in the operative note, or from a concurrent excision specimen. Clinical diagnosis alone without pathology support is insufficient for 11600-series billing.

•       Prior biopsy confirmed BCC → use 11600-series from the moment of excision

•       Clinically suspicious lesion with concurrent pathology → bill 11400-series initially; correct to 11600-series upon malignancy confirmation

•       No pathology and no malignancy diagnosis → use 11400-series benign codes only

Step 2: Measure Total Excised Diameter Including Margins

This is the step most frequently performed incorrectly. The operative note must document the surgical margins planned before excision, the lesion's clinical diameter, and the resulting total excised diameter. Many providers document only the lesion size — missing the margin addition that qualifies the encounter for a higher, more accurate code.

•       Measure the lesion's greatest clinical diameter pre-excision

•       Add the surgical margin distances on both sides in the same measurement plane

•       Document explicitly: 'Total excised diameter including 3 mm margins: 1.8 cm' — not just 'lesion: 1.2 cm'

•       Use the longest dimension of the excision for code selection when asymmetric

Step 3: Identify the Correct Anatomical Location Group

Confirm which of the three location families applies. The location must be specifically documented in the operative note. 'Right posterior shoulder' clearly falls in the trunk group. 'Right preauricular area' clearly falls in the face group. Ambiguous location documentation creates coding vulnerability.

Step 4: Select the Code Within the Correct Size Range

With lesion type, total excised diameter, and anatomical location confirmed, select the code corresponding to the total excised diameter range within the correct location group. When measurement falls at the boundary of two ranges, the documented measurement determines code selection — which is why margin inclusion in the operative note is so financially significant.

📏  Size & Margin Calculation — How It Works in Practice

Example A — Common Documentation Error: Lesion diameter = 0.8 cm. Planned margins = 0.2 cm each side. Total excised diameter = 0.8 + 0.2 + 0.2 = 1.2 cm → Correct code: 11442 (face, benign, 1.1–2.0 cm). But if provider only notes '0.8 cm lesion excised' without margins, billing defaults to 11441 (0.6–1.0 cm) — undercoded by one tier, losing $55–$75 per encounter.

Example B — Correct Documentation: Lesion diameter = 1.0 cm. Margins = 4 mm each side. Total excised diameter = 1.0 + 0.4 + 0.4 = 1.8 cm → Code: 11602 (trunk, malignant, 1.1–2.0 cm). Operative note states: 'BCC confirmed per path 03/12/26. Excised with 4 mm margins. Total excised diameter including margins: 1.8 cm.' Clean, defensible, correctly coded.

The Rule: Always document the calculation. 'Excised with ___ mm margins. Total excised diameter including margins: ___ cm.' This single documentation habit is worth thousands in annual revenue recovery.

🧾 Documentation Requirements — CPT 11400–11646 Compliance Checklist

Every excision claim must be supported by operative documentation that independently justifies lesion type, size with margins, location, and procedure method. Here is the complete 2026 documentation standard:

🧾  Excision Documentation Compliance Checklist — MedCloudMD 2026 Standard

✔  Lesion Type — Benign or Malignant: Specify the clinical or pathology-confirmed diagnosis. 'Basal cell carcinoma confirmed per biopsy 04/01/26' or 'lipoma, clinically benign.' Ambiguous descriptions support neither code family.

✔  Pre-Excision Lesion Size: Record the clinical diameter of the lesion before excision 'lesion measured 0.9 cm at greatest diameter.' This is the baseline for total excised diameter calculation.

✔  Surgical Margins Explicitly Stated: State planned margin distance '3 mm margins planned on all sides.' This is the critical missing element in most undercoded excision claims.

✔  Total Excised Diameter Calculated and Stated: 'Total excised diameter including margins: 1.6 cm.' This single line is worth one or two code tiers on every correctly documented claim.

✔  Anatomical Location Precisely Documented: 'Right lateral cheek, 2 cm anterior to the tragus.' Location determines the code group face, scalp/neck, or trunk/arms/legs.

✔  Method of Excision: 'Excised with 15-blade in elliptical fashion' or 'shave excision with horizontal blade.' Technique differentiates excision codes from biopsy or destruction codes.

✔  Closure Type: 'Closed in layers with 4-0 Vicryl subcutaneous and 5-0 Prolene cutaneous.' Closure type may be separately billable and must be documented to support those codes if billed.

✔  Pathology Submission for Malignant Codes: 'Specimen submitted to [lab] for histopathological analysis.' For 11600-series billing, pathology confirmation is required. Reference prior biopsy path result with date and accession number.

✔  Medical Necessity Statement: 'BCC excised to achieve clear margins per oncologic standards' or 'symptomatic lipoma causing functional discomfort excision per patient request and clinical recommendation.'

✔  Matching ICD-10 Diagnosis Codes: Each lesion excised requires a corresponding diagnosis code. Malignant codes require malignancy-specific ICD-10 (C44.xxx). Benign codes require appropriate benign lesion ICD-10 (D22.xxx for nevi, M88200 for lipoma).

✔  Provider Signature and Date of Service: Operative note signed and dated by the performing provider on the date of service. Unsigned or undated operative notes are indefensible in any payer audit.

💰 Reimbursement Insights — Benign vs. Malignant, Small vs. Large Excisions

Understanding the reimbursement differential across lesion type, size, and location helps your practice make informed coding decisions and identify where revenue optimization is greatest:

📈  Revenue Impact — What Correct Coding Delivers vs. Systematic Undercoding

A dermatology practice performing 15 excisions per week that consistently undercodes by one size tier due to missing margin documentation loses an average of $95 per excision × 15 × 50 weeks = $71,250 annually. That revenue was earned. The clinical work was done. The loss is entirely a documentation problem — and entirely fixable.

Practices that code malignant lesions at benign rates due to delayed pathology integration lose $75–$175 per encounter on every affected claim. At 8 malignant excisions per week, that's $30,000–$70,000 in annual revenue lost to a single correctable process gap.

📈 Revenue Recovery — Common Undercoding Scenarios & Corrections

These are the most common excision coding errors in dermatology with exact revenue gaps and root cause fixes:

🚫 Common Excision Billing Mistakes That Cause Denials and Revenue Loss

🚫  The Coding Errors Costing Dermatology Practices on Every Surgical Encounter

Not Including Margins in the Excised Diameter Measurement: The most financially significant and most common excision billing error. Providers who document lesion size without adding surgical margins systematically code their excisions at lower size tiers — losing $75–$150 per encounter on every affected claim.

Coding Malignant Excisions at Benign Rates: When pathology results arrive after initial claim submission, many practices fail to recode or submit a corrected claim. Every path-confirmed malignancy on a benign-coded claim is a permanent underpayment of $75–$175.

Using the Wrong Anatomical Location Group: A scalp excision coded in the trunk range (11402 instead of 11422) loses $35–$70 per encounter. A facial excision in the scalp range loses $45–$95. Location errors compound rapidly across high-volume practices.

Missing Modifier 25 on Same-Day E/M + Excision: The most common modifier error in excision billing. Without Modifier 25 on the E/M when a significant, separately identifiable visit occurs on the same day as an excision, the visit reimbursement is denied — typically permanently.

Not Linking Malignant Pathology to the Operative Note: The operative note for 11600-series billing must reference the prior biopsy path result with date and accession number. Missing this reference leaves the malignant designation unsupported and the claim vulnerable to denial.

Multiple Excisions Without Modifiers: Two excisions at different anatomical sites in the same session require Modifier XS or 59 on the secondary excision code. Without the modifier, the secondary excision is denied as an NCCI-bundled duplicate — and the revenue is permanently lost.

Not Billing Separately Eligible Closure Codes: Complex repairs and layered closures following excision (CPT 12031–13160) are often separately billable. Many practices absorb these without billing — leaving $150–$500+ per encounter on the table for procedures already performed.

⚠️ Modifiers That Protect Excision Reimbursement — Complete Reference

Correct modifier application is the difference between full reimbursement and a denied or permanently reduced claim on every multi-procedure excision encounter:

Modifier	Name	When It Applies	Dermatology Example
Modifier 59	Distinct Procedural Service	Two excisions at separate anatomical sites in the same session clinically distinct and not components of one procedure	Excision on back + separate excision on arm same day → Modifier 59 (or XS) on secondary excision code
Modifier XS	Separate Structure	Preferred over 59 for Medicare when excisions are on anatomically distinct structures. More specific, less audit-prone	Face excision (11442) + scalp excision (11422) same visit → XS on lower-value code for Medicare claims
Modifier 25	Significant Separately Identifiable E/M	When a significant E/M service occurs same day as an excision must be separate and distinct from the surgical decision	New patient visit (99204) + same-day excision → Modifier 25 on the E/M to prevent automatic bundling denial
Modifier 58	Staged or Related Procedure	Second procedure was planned or anticipated at time of original, or was necessary due to therapy of original procedure	Initial excision followed by planned wider re-excision within the global surgery period
Modifier 79	Unrelated Procedure During Global Period	A new, unrelated procedure performed during the global surgical period of a previous excision must be clinically independent	Patient returns for unrelated excision during 90-day global period of a prior malignant removal
Modifier 51	Multiple Procedures Same Session	Multiple surgical procedures by same provider at same operative session secondary procedures subject to fee reduction	Two significant excisions same session → Modifier 51 on secondary if payer requires (many apply automatically)

✅ Pro Tips to Maximize Dermatology Excision Revenue in 2026

✅  Expert Strategies From the MedCloudMD Excision Billing Team

Build a Margin Documentation Habit Into Every Operative Note: Train every provider to include three elements per excision note: pre-excision lesion diameter, planned margin distance, and calculated total excised diameter. This single habit eliminates the most costly systematic undercoding error in the entire code family.

Integrate Pathology Result Review Into Your Claim Correction Workflow: Establish a process where pathology results are cross-referenced against pending excision claims within 48–72 hours of receipt. Every path-confirmed malignancy on a benign-coded claim needs a corrected submission before timely filing limits apply.

Audit a Random Sample of Excision Claims Monthly: Pull 20 excision claims each month and verify: code group matches location, total excised diameter matches the size range billed, margin documentation supports the measurement, and same-day modifiers are correctly applied.

Always Check for Separately Billable Closure: Review every excision operative note for the closure method used. Layered and complex repairs (12031–13160) are separately billable and are frequently left on the table — especially in facial excisions where repair complexity is significant.

Use the Three-Dimension Framework at Point of Documentation: Lesion type + total excised diameter + anatomical location. Providers who understand all three dimensions select the right code range at documentation, not after the fact in a billing reconciliation that can only catch errors — not prevent them.

Use XS Over 59 for Same-Day Multi-Excision Medicare Claims: For Medicare and Medicare Advantage plans, Modifier XS (Separate Structure) is preferred over 59 when two excisions are performed at distinct anatomical sites. XS is more specific, more defensible, and reduces statistical Modifier 59 audit profile.

Why Outsourcing Excision Billing to a Dermatology Specialist Pays for Itself

The 11400–11646 code family requires three simultaneous correct decisions per claim, pathology result integration, operative note documentation analysis, modifier management, and same-day procedure coordination on every excision encounter your practice performs. Sustaining this level of coding precision in-house requires continuous training and specialty-specific expertise that generalist billing teams rarely maintain.

What In-House Teams Consistently Get Wrong

•       Code by lesion size without adding margins — the most common and most expensive excision undercoding error

•       Fail to recode malignant excisions when pathology confirms malignancy — leaving $75–$175 per claim permanently underpaid

•       Use the wrong location group codes — particularly at face/scalp/trunk boundaries on multiple encounters per week

•       Miss Modifier 25 on same-day E/M visits — accepting E/M denials as routine rather than preventing them

What MedCloudMD Delivers for Excision Billing

•       Operative note review on every excision claim — confirming margin documentation supports the code's size tier before submission

•       Pathology integration workflow — malignancies on pending benign-coded claims identified and corrected within 72 hours

•       Location group accuracy review — anatomical location verified against the correct code family before every submission

•       Same-day modifier compliance — Modifier 25, 59/XS, and 51 applied correctly on every qualifying multi-procedure encounter

•       Closure code capture — every operative note reviewed for separately billable repair and closure services

Our expert dermatology RCM solutions combine operative note analysis, pathology result integration, and pre-submission excision claim review delivering measurable revenue improvement starting in the first billing cycle.

🚀 Every Excision Your Practice Performs Deserves Accurate, Maximum Reimbursement

At MedCloudMD, our certified billing team reviews every 11400–11646 claim for margin inclusion, size tier accuracy, location group correctness, pathology alignment, and modifier compliance before any claim reaches the payer. We help dermatology practices recover $40,000–$120,000 in annual excision revenue that was already earned but never correctly coded.

🔍  Get a Free Dermatology Billing Audit — Uncover Your Excision Coding Gaps

Identify exactly where size, location, and margin documentation errors are costing you

📈  Increase Your Surgical Revenue Today — Starting With Your Next Excision Claim

Most practices recover $40,000–$120,000+ annually through accurate excision code selection

📞  Talk to Our Dermatology Billing Experts — Zero Pressure, Real Results

Certified excision coding specialists available for a free consultation

💼  Start Maximizing Your Excision Reimbursement — This Billing Cycle

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🏆  Why MedCloudMD — The Excision Coding Standard for Dermatology

Operative Note Review on Every Excision Claim: Every claim in the 11400–11646 family reviewed for margin documentation, size tier accuracy, and location group correctness before submission.

Pathology Integration Workflow: Path-confirmed malignancies on pending benign-coded claims identified and corrected within 72 hours of result receipt.

Dermatology-Exclusive Coding Team: Every coder specializes in dermatology surgical billing — including excision code selection logic, modifier rules, and closure code billing.

Same-Day Multi-Procedure Modifier Management: Modifier 25, 59/XS, and 51 applied correctly on every qualifying multi-procedure excision encounter.

Closure Code Capture Program: Every operative note reviewed for separately billable repair and closure codes — recovering revenue commonly left uncollected.

95–99% First-Pass Clean Claim Rate: Achieved through pre-submission excision code review and documentation completeness validation.

Quarterly Excision Coding Audit Reports: Practice-level analysis showing size tier accuracy, location group compliance, and malignant vs benign split.

No Long-Term Contracts: We earn your business with measurable results every billing cycle.

Explore Our Dermatology Billing Services: medcloudmd.com/specialties/dermatology-billing-services

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