ICD-10 C43.121
Billable / Specific HCC v28: 12Malignant melanoma of left upper eyelid, including canthus
About ICD-10-CM C43.121
ICD-10-CM code C43.121 represents Malignant melanoma of left upper eyelid, including canthus. This is a billable/specific code in the Neoplasms chapter (block C43). The 2026 edition of ICD-10-CM C43.121 became effective on October 1, 2025.
Coding Tips for C43.121
Specialist guidance from the PayerReady Medical Coding Team. Specificity warnings, HCC capture rules, sequencing notes.
C43.121 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.
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 C43.121
Local Coverage Determinations (LCDs) from CMS MACs that list C43.121 as a covered diagnosis.
Showing top 10 of 1,764 total . Click a CPT for full coverage scope.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing C43.121.
5 Medicare
CPT Codes Commonly Billed with C43.121
Procedures frequently paired with this diagnosis based on PayerReady's Dx↔Px linkage data.
- 17312 CMS LCD: Billing and Coding: Mohs Micrographic Surgery CMS LCD
- 17313 CMS LCD: Billing and Coding: Mohs Micrographic Surgery CMS LCD
- 17314 CMS LCD: Billing and Coding: Mohs Micrographic Surgery CMS LCD
- 17315 CMS LCD: Billing and Coding: Mohs Micrographic Surgery CMS LCD
- 81210 CMS LCD: Billing and Coding: MolDX: FDA-Approved BRAF Tests CMS LCD
- 17272 CMS LCD: Billing and Coding: Destruction of Malignant Skin Lesions CMS LCD
- 17280 CMS LCD: Billing and Coding: Destruction of Malignant Skin Lesions CMS LCD
- 17283 CMS LCD: Billing and Coding: Destruction of Malignant Skin Lesions CMS LCD
- 17263 CMS LCD: Billing and Coding: Destruction of Malignant Skin Lesions CMS LCD
- 17260 CMS LCD: Billing and Coding: Destruction of Malignant Skin Lesions CMS LCD
Codes Adjacent To C43.121
Other codes in section C43-C44 (Melanoma and other malignant neoplasms of skin).
ICD-10 C43.121, Billing FAQ
Is ICD-10 code C43.121 billable? +
Yes, C43.121 is a billable ICD-10-CM code that can appear as a primary or secondary diagnosis on claims.
Does C43.121 affect Medicare Advantage HCC risk adjustment? +
Yes. C43.121 maps to CMS-HCC v28 category 12. Capture this diagnosis annually for accurate Medicare Advantage risk score.
What CPT codes are commonly billed with C43.121? +
Procedures frequently paired with C43.121 include: 17312, 17313, 17314, 17315, 81210.
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Reviewed by the PayerReady Medical Coding Team
Verified against the CMS 2026 code set on May 31, 2026.
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