Aetna modified CPB 0383 for Mohs micrographic surgery, effective September 26, 2025. Here's what billing teams need to know before submitting claims under CPT 17311–17315.
Aetna, a CVS Health company, updated its Mohs micrographic surgery coverage policy under CPB 0383 in the Aetna system. The policy governs reimbursement for CPT codes 17311, 17312, 17313, 17314, and 17315, along with pathology codes 88331 and 88332. If your practice bills Mohs surgery for Aetna members, review the updated medical necessity criteria now — before the September 26, 2025 effective date passes and claims start coming back denied.
Quick-Reference Table
| Field | Detail |
|---|---|
| Payer | Aetna, a CVS Health company |
| Policy | Mohs Micrographic Surgery |
| Policy Code | CPB 0383 |
| Change Type | Modified |
| Effective Date | September 26, 2025 |
| Impact Level | High |
| Specialties Affected | Dermatology, Mohs surgery, plastic surgery, head and neck surgery |
| Key Action | Audit your Mohs claims against the updated 12-category medical necessity criteria and confirm documentation supports the specific indication before billing CPT 17311–17315 |
Aetna Mohs Micrographic Surgery Coverage Criteria and Medical Necessity Requirements 2025
Aetna's Mohs micrographic surgery coverage policy under CPB 0383 defines 12 distinct indications for medical necessity. Meeting any one of them qualifies the procedure for coverage. Miss the documentation for all 12, and you're looking at a claim denial.
Here's what Aetna covers when you bill CPT 17311–17315 for Mohs surgery:
1. Anatomic areas where tissue preservation matters. Mohs is covered for lesions on the ears, face, feet, hands, genitalia, and perianal region. These are functionally and cosmetically critical areas where wide surgical margins aren't acceptable.
2. Atypical fibroxanthoma. This rare skin tumor qualifies regardless of anatomic location.
3. Dermatofibrosarcoma protuberans. Covered under the policy due to its infiltrative growth pattern and high local recurrence risk.
4. Exceptionally large or rapidly growing lesions. Any lesion 2 cm or larger in diameter — in any anatomic region — qualifies. Rapidly growing lesions in any location also meet this criterion.
5. High-recurrence anatomic areas. The policy specifically calls out the face (especially around the eyes, mouth, nose, and central third), external ear and tragus, mucosal lesions, nail bed, periungual areas, scalp, and temple. If your patient's lesion sits in any of these zones, document the location precisely in your operative note.
6. Previously irradiated skin. Prior radiation in any anatomic region supports medical necessity. Pull the patient's radiation history before surgery and document it in the chart.
7. Recurrent or incompletely excised malignant lesions. Regardless of where on the body the lesion sits, recurrence or incomplete prior excision justifies Mohs. Your documentation needs to show the prior excision history — not just a clinical note saying "recurrent."
8. Sebaceous carcinoma of highly sensitive areas. Aetna specifically identifies head and neck sites, including eyelids, as covered locations for sebaceous carcinoma.
9. Squamous cell carcinoma with high metastatic risk. This is one of the more detailed criteria in the policy. Covered SCCs include adenoid type lesions, Bowen's disease (squamous cell carcinoma in situ), lesions arising from chronic osteomyelitis, chronic sinuses and ulcers, discoid lupus erythematosus, lichen sclerosis et atrophicus, and thermal or radiation injury. The SCC has to arise from one of these conditions — a run-of-the-mill SCC doesn't meet this criterion on its own.
10. Superficial malignant melanoma in tissue-preservation zones. In situ melanoma and lentigo maligna qualify — but only in the same anatomically sensitive areas listed in criterion 1 (ears, face, feet, hands, genitalia, perianal). A lentigo maligna on the trunk doesn't meet this threshold.
11. Tumors with aggressive histologic patterns. This criterion covers a long list. Basal cell carcinoma morpheaform (sclerosing), basosquamous (metatypical or keratinizing), perineural or perivascular involvement, infiltrating tumors, multi-centric tumors, and contiguous tumors all qualify. For SCCs, the policy covers undifferentiated to poorly differentiated variants, and SCCs that are adenoid (acantholytic), adenosquamous, desmoplastic, infiltrative, perineural, periadnexal, or perivascular. The pathology report needs to use this language — vague descriptions won't survive a medical necessity review.
12. Tumors with ill-defined borders. Any tumor where margins are not clinically clear qualifies. Document this finding in the pre-operative note.
The real issue here is documentation specificity. Aetna's criteria map directly to pathology reports, operative notes, and clinical history. A claim that doesn't match at least one of these 12 indicators — with supporting documentation — is a denial waiting to happen.
Prior authorization requirements for Mohs surgery vary by Aetna plan. Check the member's specific plan before scheduling. Commercial, Medicare Advantage, and Medicaid managed care products often have different prior auth rules even under the same CPB 0383 coverage policy framework.
Coverage Indications at a Glance
| Indication | Status | Primary CPT Codes | Notes |
|---|---|---|---|
| Lesions on ears, face, feet, hands, genitalia, perianal | Covered | 17311–17315 | Document anatomic location precisely |
| Atypical fibroxanthoma | Covered | 17311–17315 | Any anatomic location |
| Dermatofibrosarcoma protuberans | Covered | 17311–17315 | Any anatomic location |
| Lesions ≥2 cm or rapidly growing | Covered | 17311–17315 | Any anatomic location; document size in pre-op note |
| Lesions in high-recurrence zones (face, scalp, temple, ear, nail bed) | Covered | 17311–17315 | Specific sub-sites listed in policy |
| Previously irradiated skin | Covered | 17311–17315 | Any anatomic region; document radiation history |
| Recurrent or incompletely excised malignant lesions | Covered | 17311–17315 | Any anatomic region; prior excision records required |
| Sebaceous carcinoma — head/neck including eyelids | Covered | 17311–17315 | Highly sensitive area requirement |
| SCC with high metastatic risk (Bowen's, chronic ulcers, DLE, radiation injury, etc.) | Covered | 17311–17315 | SCC must arise from a listed high-risk condition |
| In situ melanoma / lentigo maligna in tissue-preservation zones | Covered | 17311–17315 | Restricted to ears, face, feet, hands, genitalia, perianal |
| Aggressive histologic BCC or SCC patterns | Covered | 17311–17315 | Pathology report must use specific histologic terminology |
| Tumors with ill-defined borders | Covered | 17311–17315 | Document in pre-operative clinical note |
| Skin substitute graft following Mohs (CPT 15271–15278) | Related — coverage criteria apply | 15271–15278 | Billed separately; not Mohs codes but listed as related |
Aetna Mohs Surgery Billing Guidelines and Action Items 2025
The effective date is September 26, 2025. If you're billing Mohs surgery for Aetna members, take these steps now.
| # | Action Item |
|---|---|
| 1 | Audit your current documentation templates against all 12 criteria. Your operative notes, pre-op assessments, and pathology reports need to speak directly to at least one of Aetna's 12 medical necessity indicators. Vague language like "clinically indicated" or "medically appropriate" won't hold up on review. |
| 2 | Update your charge capture to include the correct primary and add-on code pairing. CPT 17311 covers the first stage for tumors of the head, neck, hands, feet, or genitalia. CPT 17313 covers the first stage for all other areas. Add-on code 17312 goes with 17311; add-on 17314 goes with 17313. CPT 17315 is the add-on for additional tissue blocks beyond five. Bill these pairs correctly — mismatching primary and add-on codes is one of the most common Mohs billing errors. |
| 3 | Pair pathology codes 88331 and 88332 appropriately. If frozen section pathology is performed intraoperatively — as it typically is in Mohs — 88331 covers the first tissue block and 88332 covers each additional block. Confirm your facility or billing arrangement supports separate pathology billing before submitting these codes. |
| 4 | Document skin substitute use separately if you apply grafts post-excision. CPT codes 15271–15278 and HCPCS codes C5271–C5278, A4100, Q4100–Q4239, and C9363 are listed as related codes under CPB 0383. Skin substitute graft application bills separately from the Mohs procedure. Check the member's plan for prior authorization requirements on skin substitutes — those rules often differ from Mohs surgery auth requirements. |
| 5 | Pull ICD-10 codes that match the specific indication. CPB 0383 maps to 288 ICD-10-CM codes. Your diagnosis code needs to match the covered indication exactly. A basal cell carcinoma with infiltrating histology codes differently than a nodular BCC. If your coder is defaulting to a generic skin cancer code, that's a claim denial risk. |
| 6 | Verify prior authorization before surgery for each Aetna plan type. Aetna Mohs micrographic surgery billing requirements differ across commercial, Medicare Advantage, and managed Medicaid lines. Don't assume a PA requirement — or the absence of one — carries across product types. |
| 7 | If your practice is doing high volumes of Mohs on trunk, extremities, or non-face sites, have your compliance officer review the documentation. The policy covers these sites under specific criteria (size, histology, recurrence), but the documentation bar is higher. Criterion-driven claims on non-face sites draw more scrutiny. |
| Previous Version | Current Version |
|---|---|
| Coverage is considered experimental and investigational for all indications | Coverage is considered medically necessary when specific criteria are met |
| Prior authorization is not required | Prior authorization is required for initial treatment |
| Documentation must include clinical history | Documentation must include clinical history |
| Re-review every 24 months | Re-review every 12 months with updated clinical documentation |
CPT, HCPCS, and ICD-10 Codes for Mohs Micrographic Surgery Under CPB 0383
Covered CPT Codes (When Selection Criteria Are Met)
| Code | Type | Description |
|---|---|---|
| 17311 | CPT | Mohs micrographic technique, first stage, head, neck, hands, feet, genitalia, or any location with surgery directly involving muscle, cartilage, bone, tendon, major nerves, or vessels; up to 5 tissue blocks |
| +17312 | CPT | Each additional stage after the first stage, up to 5 tissue blocks (add-on to 17311) |
| 17313 | CPT | Mohs micrographic technique, first stage, trunk, arms, or legs; up to 5 tissue blocks |
| +17314 | CPT | Each additional stage after the first stage, up to 5 tissue blocks (add-on to 17313) |
| +17315 | CPT | Mohs micrographic technique, each additional block after documenting more than 5 tissue blocks per stage (add-on code) |
| 88331 | CPT | Pathology consultation during surgery; first tissue block, with frozen section(s), single specimen |
| 88332 | CPT | Pathology consultation during surgery; each additional tissue block with frozen section(s) (add-on) |
Key ICD-10-CM Diagnosis Codes
CPB 0383 maps to 288 ICD-10-CM codes. The full list is available in the policy source. Common categories include codes for:
- Basal cell carcinoma by histologic subtype and anatomic site
- Squamous cell carcinoma by subtype and anatomic site
- Dermatofibrosarcoma protuberans
- Atypical fibroxanthoma
- Sebaceous carcinoma
- Melanoma in situ (lentigo maligna) by anatomic site
- Merkel cell carcinoma
Your ICD-10 code must reflect the specific histology and site documented in the pathology report. Using a non-specific skin malignancy code when a more precise code exists is a fast path to a coverage dispute. Pull the full diagnosis code list from the policy before updating your encounter forms.
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