How do you choose the correct CPT code for a benign or malignant skin lesion excision? The answer depends on more than the lesion’s visible size. Accurate coding requires the total excised diameter, the anatomical site, and the clinical findings that support the lesion’s classification.
For dermatology billing teams, even a small difference in margin measurements can affect code selection. Understanding how to calculate excision size, distinguish the relevant CPT code ranges, and interpret pathology findings helps coders select codes that accurately reflect the procedure performed.
This guide explains how to calculate total excised diameter, select benign and malignant lesion excision CPT codes by anatomical site, and distinguish excision from shave removal to support accurate, well-documented claims.
How to Select Benign Lesion Excision CPT Codes
CPT codes 11400–11446 describe excision of benign skin lesions, including margins, with code selection based on the excised diameter and anatomical site. These codes apply to full-thickness removal through the dermis and include simple, non-layered closure when performed.
The correct code depends on three factors:
- Lesion classification: Whether the lesion is benign or the procedure meets the applicable criteria for excision of a malignant or suspicious lesion.
- Excised diameter: The greatest clinical diameter of the lesion plus the required margins.
- Anatomical site: The code family for the trunk, arms, or legs; scalp, neck, hands, feet, or genitalia; or face and specified facial structures.
The provider’s operative documentation should support the procedure, location, and size. For Medicare claims, medical necessity and applicable local coverage requirements must also be considered.
For additional coding guidance, review the CMS Billing and Coding: Removal of Benign Skin Lesions.
How to Calculate Excision Size for Medical Coding
The excised diameter is not necessarily the same as the lesion’s visible diameter. It includes the lesion and the margins required for complete excision.
The measurement should be documented before excision. CMS guidance explains that code selection is based on the greatest clinical diameter of the apparent lesion plus the margin required for complete removal.
Excision size formula
Excised diameter = Lesion diameter + margins on both sides
When the margin width is equal on both sides:
Excised diameter = Lesion diameter + (2 × margin width)
For unequal margins, add the individual margin measurements to the lesion diameter.
Example 1: Equal margins
A benign lesion on the forearm measures 0.8 cm across. The provider plans a 0.2 cm margin on each side.
| Measurement | Diameter |
| Lesion | 0.8 cm |
| Margin on one side | 0.2 cm |
| Margin on the opposite side | 0.2 cm |
| Total excised diameter | 1.2 cm |
The reportable excised diameter is 1.2 cm, not 0.8 cm. Assuming the documentation supports the procedure and site, the corresponding benign lesion code is 11402, which covers an excised diameter of 1.1–2.0 cm for the trunk, arms, or legs.
Example 2: Unequal margins
A lesion measures 0.8 cm. The documented margins are 0.1 cm on one side and 0.2 cm on the other. The calculation is:
0.8 + 0.1 + 0.2 = 1.1 cm
The resulting diameter falls within the 1.1–2.0 cm size range. For a benign lesion on the trunk, arm, or leg, this corresponds to CPT 11402.
These examples illustrate code selection by size and site. Coders should use the provider’s documented measurements rather than estimating margins or inferring missing details.
Benign Lesion Excision CPT Code Reference
Use the following table as a quick reference for the commonly used benign excision code families. Confirm the complete descriptor and applicable code-year requirements in the current CPT codebook.
| Excised diameter | Trunk, arms, legs | Scalp, neck, hands, feet, genitalia | Face and specified facial structures |
| 0.5 cm or less | 11400 | 11420 | 11440 |
| 0.6–1.0 cm | 11401 | 11421 | 11441 |
| 1.1–2.0 cm | 11402 | 11422 | 11442 |
| 2.1–3.0 cm | 11403 | 11423 | 11443 |
| 3.1–4.0 cm | 11404 | 11424 | 11444 |
| Over 4.0 cm | 11406 | 11426 | 11446 |
Important: The middle and facial groups have specific anatomical wording in their CPT descriptors. Do not assign a code based on a broad body-region label alone. Verify the exact site against the current code descriptor, particularly for eyelids, lips, mucous membranes, ears, and other specialized locations.
Malignant Lesion Excision CPT Codes
CPT codes 11600–11646 describe excision of malignant skin lesions, including margins. As with benign excisions, the code family depends on the excised diameter and anatomical site.
The clinical record must support the procedure performed and the diagnosis reported. CMS guidance for malignant skin lesion excision calls for documentation of the lesion’s size and location in the operative report and supporting pathology documentation where applicable.
Malignant lesion excision code reference
| Excised diameter | Trunk, arms, legs | Scalp, neck, hands, feet, genitalia | Face and specified facial structures |
| 0.5 cm or less | 11600 | 11620 | 11640 |
| 0.6–1.0 cm | 11601 | 11621 | 11641 |
| 1.1–2.0 cm | 11602 | 11622 | 11642 |
| 2.1–3.0 cm | 11603 | 11623 | 11643 |
| 3.1–4.0 cm | 11604 | 11624 | 11644 |
| Over 4.0 cm | 11606 | 11626 | 11646 |
The table summarizes the main size ranges and code families. Verify the exact anatomical wording in the current CPT codebook before assigning a code.
For Medicare-specific guidance, consult CMS Billing and Coding: Excision of Malignant Skin Lesions.
Example: Malignant lesion on the scalp
Suppose the documented excised diameter is 1.6 cm and the lesion is classified and treated as malignant. The scalp belongs to the relevant head-and-neck code family, so CPT 11622 is the corresponding size-range code, provided the operative record and exact site support that selection.
The example demonstrates the size-and-site process. It does not replace review of the full descriptor or payer requirements.
How Pathology Findings Affect Excision Coding
Pathology results are important, but coders should not select a procedure code based on the pathology report alone. The code must describe the procedure actually performed and be supported by the clinical and operative documentation.
Before claim submission, reconcile the pathology findings with the provider’s documented diagnosis and procedure. If the findings differ from the preoperative assessment, follow the practice’s established clarification process when the record does not adequately support the submitted diagnosis or code.
CMS guidance also distinguishes an excision of a lesion with moderate-to-high suspicion of malignancy from routine removal of a benign lesion. The applicable coding and coverage requirements should be reviewed for the specific case.
Excision vs. Shave Removal: Which CPT Codes Apply?
Excision and shave removal describe different techniques. They should not be treated as interchangeable simply because both involve removing a skin lesion.
| Procedure | General description | Coding consideration |
| Full-thickness excision | Removes the lesion through the dermis, including the required margins | Benign or malignant excision code family, as supported by the case |
| Shave removal | Removes an epidermal or dermal lesion by shaving, without full-thickness excision | Consider the applicable shave-removal code family, CPT 11300–11313 |
| Tangential biopsy | Removes tissue primarily to obtain a diagnostic specimen | Consider CPT 11102–11103, as applicable, rather than reporting shave removal for the same biopsy procedure |
The actual technique, purpose, and documentation determine the appropriate code. A pathology specimen does not automatically make a procedure a biopsy, and a shave procedure should not be reported as a full-thickness excision when the documentation does not support it.
CMS provides further detail in its benign skin lesion billing and coding guidance.
Documentation Checklist for Accurate Dermatology Coding
Before submitting a lesion excision claim, confirm that the medical record supports each element below:
- The diagnosis or lesion classification is documented.
- The procedure and technique performed are clearly described.
- The anatomical site is specific enough to support the code family.
- The greatest clinical diameter and required margins are documented.
- The total excised diameter is calculated correctly and measured before excision.
- Pathology findings are reviewed when applicable and reconciled with the clinical record.
- The selected CPT descriptor matches the documented procedure, site, and size.
- Applicable payer coverage, medical-necessity, and claim-edit requirements have been checked.
Missing measurements or unclear anatomical descriptions should be clarified through the practice’s normal documentation workflow rather than resolved by guessing.
Improve Dermatology Billing Accuracy With ORCM
Accurate lesion excision coding starts with clear documentation of lesion size, margins, anatomical site, and pathology findings. When these details are incomplete or inconsistent, claims may require clarification or correction, delaying reimbursement and increasing administrative work.
ORCM helps dermatology practices strengthen their billing workflows through specialized dermatology billing services that support coding accuracy, documentation review, and claim management. A consistent review process helps billing teams identify missing information and ensure that submitted claims reflect the documented procedure.
Final Takeaway
Selecting the correct benign or malignant lesion excision CPT code requires accurate measurement, precise anatomical site identification, and documentation that supports the lesion’s classification and the procedure performed.
By calculating the total excised diameter using the lesion’s greatest clinical diameter and the narrowest required margins, dermatology billing teams can select the appropriate code range with greater confidence.
Reviewing pathology findings alongside the operative report and verifying the applicable CPT descriptor helps support accurate claims, meet documentation requirements, and reduce avoidable coding errors.
Frequently Asked Questions
1. How do you calculate excision size for medical coding?
Add the lesion’s greatest clinical diameter to the margins required for excision on both sides. For example, a 0.8 cm lesion with 0.2 cm margins on each side has a total excised diameter of 1.2 cm. The measurement should be documented before excision.
2. What CPT codes are used for benign lesion excision?
CPT 11400–11446 are used for full-thickness excision of benign skin lesions, including margins. The specific code depends on the excised diameter and anatomical site, as documented in the medical record.
3. What CPT codes are used for malignant lesion excision?
CPT 11600–11646 cover excision of malignant skin lesions, including margins. Code selection depends on the documented excised diameter and anatomical site, with the current CPT descriptor verified before billing.
4. Does lesion size or excised diameter determine the CPT code?
The excised diameter is the relevant measurement for these excision code families. It includes the lesion’s greatest clinical diameter and the margins required for complete excision, not just the visible lesion.
5. Can a coder use the pathology report alone to select an excision code?
No. Pathology is important to diagnosis and coding support, but the procedure code must also match the technique performed, anatomical site, excised diameter, and operative documentation.
6. What is the difference between excision and shave removal?
Full-thickness excision removes the lesion through the dermis and includes the required margins. Shave removal removes an epidermal or dermal lesion by shaving without full-thickness excision. The documented technique determines which code family applies.
7. What should coders do if the margins or lesion size are missing?
Do not estimate the missing measurements. Follow the practice’s documentation clarification process and obtain the information needed to support accurate code selection before submitting the claim.
