ICD-10 C43.9
Billable / Specific HCC v28: 12Malignant melanoma of skin, unspecified
About ICD-10-CM C43.9
ICD-10-CM code C43.9 represents Malignant melanoma of skin, unspecified. This is a billable/specific code in the Neoplasms chapter (block C43). The 2026 edition of ICD-10-CM C43.9 became effective on October 1, 2025.
Coding Tips for C43.9
Specialist guidance from the PayerReady Medical Coding Team. Specificity warnings, HCC capture rules, sequencing notes.
C43.9 is a CMS-HCC v28 risk-adjustment code (category 12). To count for the patient Risk Adjustment Factor (RAF), document the diagnosis with MEAT language each calendar year: Monitored, Evaluated, Assessed, Treated. A diagnosis on the problem list alone does not satisfy CMS RADV audit standards. Include the diagnosis in the assessment with current status and current treatment plan.
Inclusion Terms / Approximate Synonyms
Clinical terms and conditions classified under C43.9. Per CMS ICD-10-CM Tabular 2026.
- Malignant melanoma of unspecified site of skin
- Melanoma (malignant) NOS
Medicare Advantage HCC Impact
Capture this diagnosis annually for accurate risk adjustment. Missed HCC captures are the #1 revenue leak in Medicare Advantage risk programs.
Medicare LCD Coverage for C43.9
Local Coverage Determinations (LCDs) from CMS MACs that list C43.9 as a covered diagnosis.
Showing top 10 of 962 total . Click a CPT for full coverage scope.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing C43.9.
2 Aetna
5 Medicare
CPT Codes Commonly Billed with C43.9
Procedures frequently paired with this diagnosis based on PayerReady's Dx↔Px linkage data.
- 11102 Tangential skin biopsy — uncertain neoplasm skin, actinic keratosis, melanocytic nevi, skin cancer, melanoma, psoriasis, discoid lupus, skin disorder, rash, seborrheic keratosis, benign neoplasm, dermatitis, prurigo, dermatitis herpetiformis Dermatology
- 11104 Punch biopsy skin — uncertain skin neoplasm, skin cancer, melanoma, nevi, psoriasis, lupus, connective tissue disorder, pemphigus, bullous pemphigoid Dermatology
- 11106 Incisional biopsy skin — uncertain neoplasm, skin cancer, melanoma, nevi, actinic keratosis, BCC/SCC by site Dermatology
- 11600 Excision malignant lesion — skin cancer (BCC, SCC) all sites, melanoma, melanoma in situ Dermatology
- 17311 Mohs surgery first stage — skin cancer all sites, melanoma Dermatology
- 81210 CMS LCD: Billing and Coding: MolDX: FDA-Approved BRAF Tests CMS LCD
Convert C43.9 to ICD-9-CM
Per CMS General Equivalence Mappings (GEMs), useful for legacy data review and historical claim analysis.
| ICD-10 | ICD-9 | Mapping Flags |
|---|---|---|
| C43.9 | 1729 | 10000 |
Flags format (5 digits): Approximate · No Map · Combination · Scenario · Choice List. Source: CMS 2017 GEMs (final version).
Codes Adjacent To C43.9
Other codes in section C43-C44 (Melanoma and other malignant neoplasms of skin).
ICD-10 C43.9, Billing FAQ
Is ICD-10 code C43.9 billable? +
Yes, C43.9 is a billable ICD-10-CM code that can appear as a primary or secondary diagnosis on claims.
What other names or terms map to C43.9? +
ICD-10 C43.9 includes: Malignant melanoma of unspecified site of skin; Melanoma (malignant) NOS.
Does C43.9 affect Medicare Advantage HCC risk adjustment? +
Yes. C43.9 maps to CMS-HCC v28 category 12. Capture this diagnosis annually for accurate Medicare Advantage risk score.
What CPT codes are commonly billed with C43.9? +
Procedures frequently paired with C43.9 include: 11102, 11104, 11106, 11600, 17311.
What ICD-9 codes does C43.9 map to? +
Per CMS GEMs, C43.9 maps to ICD-9 codes: 1729. Useful for legacy data review and historical claim analysis.
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Reviewed by the PayerReady Medical Coding Team
Verified against the CMS 2026 code set on July 16, 2026.
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