MCMedicalCodingSoftware
C4A.1

C4A.1: Merkel cell carcinoma of eyelid, including canthus

Non-billable headerICD-10-CM

C4A.1 is a non-billable header ICD-10-CM code for merkel cell carcinoma of eyelid, including canthus. It cannot be billed on its own: choose one of the more specific child codes below.

Other codes that can never be billed with C4A.1

Their own Excludes1 notes name this code, so the conflict is not listed above.

  • C44Other and unspecified malignant neoplasm of skin

Risk adjustment

No CMS-HCC V28 category: this code does not change a RAF score.

Code history

Unchanged in every release from FY2024 to FY2027.

Code to one of these instead C4A.1

3 child codes. Green means billable.

Other codes under C4A

ICD-10-CMFY2027· effective October 1, 2026

Loaded directly from the CMS/NCHS ICD-10-CM public-domain release: see data sources and our editorial policy. If this page disagrees with the CMS tabular list, this page is wrong. Reference information for professional coders; not medical or billing advice.